21031543551 has 32 divisors (see below), whose sum is σ = 29522880000. Its totient is φ = 13291929728.

The previous prime is 21031543549. The next prime is 21031543567. The reversal of 21031543551 is 15534513012.

It is a cyclic number.

It is not a de Polignac number, because 21031543551 - 2¹ = 21031543549 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21031543571) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5231020 + ... + 5235038.

It is an arithmetic number, because the mean of its divisors is an integer number (922590000).

Almost surely, 2^21031543551 is an apocalyptic number.

21031543551 is a deficient number, since it is larger than the sum of its proper divisors (8491336449).

21031543551 is a wasteful number, since it uses less digits than its factorization.

21031543551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4703.

The product of its (nonzero) digits is 9000, while the sum is 30.

The spelling of 21031543551 in words is "twenty-one billion, thirty-one million, five hundred forty-three thousand, five hundred fifty-one".