21167406557 has 8 divisors (see below), whose sum is σ = 23103121440. Its totient is φ = 19233592560.

The previous prime is 21167406541. The next prime is 21167406599. The reversal of 21167406557 is 75560476112.

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

It is a cyclic number.

It is not a de Polignac number, because 21167406557 - 2⁴ = 21167406541 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 (21167426557) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 451883 + ... + 496520.

It is an arithmetic number, because the mean of its divisors is an integer number (2887890180).

Almost surely, 2^21167406557 is an apocalyptic number.

It is an amenable number.

21167406557 is a deficient number, since it is larger than the sum of its proper divisors (1935714883).

21167406557 is a wasteful number, since it uses less digits than its factorization.

21167406557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 950443.

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

It can be divided in two parts, 21167 and 406557, that added together give a palindrome (427724).

The spelling of 21167406557 in words is "twenty-one billion, one hundred sixty-seven million, four hundred six thousand, five hundred fifty-seven".