21041551231 has 4 divisors (see below), whose sum is σ = 21109209264. Its totient is φ = 20973893200.

The previous prime is 21041551211. The next prime is 21041551249. The reversal of 21041551231 is 13215514012.

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 21041551231 - 2¹⁹ = 21041026943 is a prime.

It is a super-2 number, since 2×21041551231² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21041551196 and 21041551205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21041551211) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33828550 + ... + 33829171.

It is an arithmetic number, because the mean of its divisors is an integer number (5277302316).

Almost surely, 2^21041551231 is an apocalyptic number.

21041551231 is a deficient number, since it is larger than the sum of its proper divisors (67658033).

21041551231 is an equidigital number, since it uses as much as digits as its factorization.

21041551231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67658032.

The product of its (nonzero) digits is 1200, while the sum is 25.

The spelling of 21041551231 in words is "twenty-one billion, forty-one million, five hundred fifty-one thousand, two hundred thirty-one".