21575567797 has 4 divisors (see below), whose sum is σ = 24657791776. Its totient is φ = 18493343820.

The previous prime is 21575567773. The next prime is 21575567803. The reversal of 21575567797 is 79776557512.

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 not a de Polignac number, because 21575567797 - 2¹⁵ = 21575535029 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21575567707) 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, 1541111979 + ... + 1541111992.

It is an arithmetic number, because the mean of its divisors is an integer number (6164447944).

Almost surely, 2^21575567797 is an apocalyptic number.

It is an amenable number.

21575567797 is a deficient number, since it is larger than the sum of its proper divisors (3082223979).

21575567797 is an equidigital number, since it uses as much as digits as its factorization.

21575567797 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3082223978.

The product of its digits is 32413500, while the sum is 61.

The spelling of 21575567797 in words is "twenty-one billion, five hundred seventy-five million, five hundred sixty-seven thousand, seven hundred ninety-seven".