21054010656 has 192 divisors, whose sum is σ = 67331174400. Its totient is φ = 5626423296.

The previous prime is 21054010589. The next prime is 21054010661. The reversal of 21054010656 is 65601045012.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 998236 + ... + 1019108.

It is an arithmetic number, because the mean of its divisors is an integer number (350683200).

Almost surely, 2^21054010656 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21054010656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33665587200).

21054010656 is an abundant number, since it is smaller than the sum of its proper divisors (46277163744).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21054010656 is a wasteful number, since it uses less digits than its factorization.

21054010656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20991 (or 20983 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 30.

Adding to 21054010656 its reverse (65601045012), we get a palindrome (86655055668).

The spelling of 21054010656 in words is "twenty-one billion, fifty-four million, ten thousand, six hundred fifty-six".