21057211567 has 16 divisors (see below), whose sum is σ = 25344793600. Its totient is φ = 17090442720.

The previous prime is 21057211531. The next prime is 21057211577. The reversal of 21057211567 is 76511275012.

It is a cyclic number.

It is not a de Polignac number, because 21057211567 - 2¹⁹ = 21056687279 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21057211507) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 230842 + ... + 308872.

It is an arithmetic number, because the mean of its divisors is an integer number (1584049600).

Almost surely, 2^21057211567 is an apocalyptic number.

21057211567 is a deficient number, since it is larger than the sum of its proper divisors (4287582033).

21057211567 is a wasteful number, since it uses less digits than its factorization.

21057211567 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80086.

The product of its (nonzero) digits is 29400, while the sum is 37.

Adding to 21057211567 its reverse (76511275012), we get a palindrome (97568486579).

The spelling of 21057211567 in words is "twenty-one billion, fifty-seven million, two hundred eleven thousand, five hundred sixty-seven".