21582551057 has 4 divisors (see below), whose sum is σ = 21617418480. Its totient is φ = 21547683636.

The previous prime is 21582551033. The next prime is 21582551077. The reversal of 21582551057 is 75015528512.

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 21582551057 - 2¹⁶ = 21582485521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21582551027) 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, 17432783 + ... + 17434020.

It is an arithmetic number, because the mean of its divisors is an integer number (5404354620).

Almost surely, 2^21582551057 is an apocalyptic number.

It is an amenable number.

21582551057 is a deficient number, since it is larger than the sum of its proper divisors (34867423).

21582551057 is an equidigital number, since it uses as much as digits as its factorization.

21582551057 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34867422.

The product of its (nonzero) digits is 140000, while the sum is 41.

The spelling of 21582551057 in words is "twenty-one billion, five hundred eighty-two million, five hundred fifty-one thousand, fifty-seven".