21570034561 has 4 divisors (see below), whose sum is σ = 21712882624. Its totient is φ = 21427186500.

The previous prime is 21570034543. The next prime is 21570034567. The reversal of 21570034561 is 16543007512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21570034561 - 2⁹ = 21570034049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21570034567) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 71423805 + ... + 71424106.

It is an arithmetic number, because the mean of its divisors is an integer number (5428220656).

Almost surely, 2^21570034561 is an apocalyptic number.

It is an amenable number.

21570034561 is a deficient number, since it is larger than the sum of its proper divisors (142848063).

21570034561 is a wasteful number, since it uses less digits than its factorization.

21570034561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142848062.

The product of its (nonzero) digits is 25200, while the sum is 34.

The spelling of 21570034561 in words is "twenty-one billion, five hundred seventy million, thirty-four thousand, five hundred sixty-one".