21254556431 has 16 divisors (see below), whose sum is σ = 22141002240. Its totient is φ = 20378598240.

The previous prime is 21254556413. The next prime is 21254556437. The reversal of 21254556431 is 13465545212.

It is a cyclic number.

It is not a de Polignac number, because 21254556431 - 2¹⁸ = 21254294287 is a prime.

It is a super-2 number, since 2×21254556431² (a number of 21 digits) 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 (21254556437) 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, 7781336 + ... + 7784066.

It is an arithmetic number, because the mean of its divisors is an integer number (1383812640).

Almost surely, 2^21254556431 is an apocalyptic number.

21254556431 is a deficient number, since it is larger than the sum of its proper divisors (886445809).

21254556431 is a wasteful number, since it uses less digits than its factorization.

21254556431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4534.

The product of its digits is 144000, while the sum is 38.

The spelling of 21254556431 in words is "twenty-one billion, two hundred fifty-four million, five hundred fifty-six thousand, four hundred thirty-one".