21056824801 has 8 divisors (see below), whose sum is σ = 22898042280. Its totient is φ = 19282560768.

The previous prime is 21056824781. The next prime is 21056824819. The reversal of 21056824801 is 10842865012.

It can be written as a sum of positive squares in 4 ways, for example, as 6069189025 + 14987635776 = 77905^2 + 122424^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21056824801 - 2⁵ = 21056824769 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21056824871) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16737706 + ... + 16738963.

It is an arithmetic number, because the mean of its divisors is an integer number (2862255285).

Almost surely, 2^21056824801 is an apocalyptic number.

It is an amenable number.

21056824801 is a deficient number, since it is larger than the sum of its proper divisors (1841217479).

21056824801 is a wasteful number, since it uses less digits than its factorization.

21056824801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33476723.

The product of its (nonzero) digits is 30720, while the sum is 37.

The spelling of 21056824801 in words is "twenty-one billion, fifty-six million, eight hundred twenty-four thousand, eight hundred one".