21557611680812 has 24 divisors (see below), whose sum is σ = 39763063846800. Its totient is φ = 10210762068416.

The previous prime is 21557611680769. The next prime is 21557611680821. The reversal of 21557611680812 is 21808611675512.

It is a Harshad number since it is a multiple of its sum of digits (53).

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, 1753215362 + ... + 1753227657.

It is an arithmetic number, because the mean of its divisors is an integer number (1656794326950).

Almost surely, 2^{21557611680812} is an apocalyptic number.

It is an amenable number.

21557611680812 is a deficient number, since it is larger than the sum of its proper divisors (18205452165988).

21557611680812 is a wasteful number, since it uses less digits than its factorization.

21557611680812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3506443105 (or 3506443103 counting only the distinct ones).

The product of its (nonzero) digits is 1612800, while the sum is 53.

The spelling of 21557611680812 in words is "twenty-one trillion, five hundred fifty-seven billion, six hundred eleven million, six hundred eighty thousand, eight hundred twelve".