21025354231 has 16 divisors (see below), whose sum is σ = 25473934080. Its totient is φ = 16940638080.

The previous prime is 21025354171. The next prime is 21025354237. The reversal of 21025354231 is 13245352012.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21025354231 is a prime.

It is a super-2 number, since 2×21025354231² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21025354231.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21025354237) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12421 + ... + 205438.

It is an arithmetic number, because the mean of its divisors is an integer number (1592120880).

Almost surely, 2^21025354231 is an apocalyptic number.

21025354231 is a deficient number, since it is larger than the sum of its proper divisors (4448579849).

21025354231 is a wasteful number, since it uses less digits than its factorization.

21025354231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 218694.

The product of its (nonzero) digits is 7200, while the sum is 28.

The spelling of 21025354231 in words is "twenty-one billion, twenty-five million, three hundred fifty-four thousand, two hundred thirty-one".