21541031 has 4 divisors (see below), whose sum is σ = 22066464. Its totient is φ = 21015600.

The previous prime is 21541027. The next prime is 21541033. The reversal of 21541031 is 13014512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21541031 - 2² = 21541027 is a prime.

It is a super-2 number, since 2×21541031² = 928032033085922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21541033) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 262655 + ... + 262736.

It is an arithmetic number, because the mean of its divisors is an integer number (5516616).

Almost surely, 2^21541031 is an apocalyptic number.

21541031 is a deficient number, since it is larger than the sum of its proper divisors (525433).

21541031 is an equidigital number, since it uses as much as digits as its factorization.

21541031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 525432.

The product of its (nonzero) digits is 120, while the sum is 17.

The square root of 21541031 is about 4641.2316253339. The cubic root of 21541031 is about 278.2416639884.

Adding to 21541031 its reverse (13014512), we get a palindrome (34555543).

The spelling of 21541031 in words is "twenty-one million, five hundred forty-one thousand, thirty-one".