21031090441 has 3 divisors (see below), whose sum is σ = 21031235463. Its totient is φ = 21030945420.

The previous prime is 21031090393. The next prime is 21031090489. The reversal of 21031090441 is 14409013012.

It is a happy number.

The square root of 21031090441 is 145021.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is an interprime number because it is at equal distance from previous prime (21031090393) and next prime (21031090489).

It can be written as a sum of positive squares in only one way, i.e., 2854658041 + 18176432400 = 53429^2 + 134820^2 .

It is not a de Polignac number, because 21031090441 - 2¹⁵ = 21031057673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21031091441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 72511 + ... + 217531.

It is an arithmetic number, because the mean of its divisors is an integer number (7010411821).

Almost surely, 2^21031090441 is an apocalyptic number.

21031090441 is the 145021-st square number.

21031090441 is the 72511-st centered octagonal number.

It is an amenable number.

21031090441 is a deficient number, since it is larger than the sum of its proper divisors (145022).

21031090441 is an frugal number, since it uses more digits than its factorization.

21031090441 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 290042 (or 145021 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 25.

Multiplying 21031090441 by its sum of digits (25), we get a square (525777261025 = 725105²).

The spelling of 21031090441 in words is "twenty-one billion, thirty-one million, ninety thousand, four hundred forty-one".