21567761045 has 8 divisors (see below), whose sum is σ = 25882101720. Its totient is φ = 17253683200.

The previous prime is 21567761029. The next prime is 21567761053. The reversal of 21567761045 is 54016776512.

It can be written as a sum of positive squares in 4 ways, for example, as 2596004401 + 18971756644 = 50951^2 + 137738^2 .

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

It is not a de Polignac number, because 21567761045 - 2⁴ = 21567761029 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21567760987 and 21567761005.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 285245 + ... + 352845.

It is an arithmetic number, because the mean of its divisors is an integer number (3235262715).

Almost surely, 2^21567761045 is an apocalyptic number.

It is an amenable number.

21567761045 is a deficient number, since it is larger than the sum of its proper divisors (4314340675).

21567761045 is an equidigital number, since it uses as much as digits as its factorization.

21567761045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131415.

The product of its (nonzero) digits is 352800, while the sum is 44.

The spelling of 21567761045 in words is "twenty-one billion, five hundred sixty-seven million, seven hundred sixty-one thousand, forty-five".