21770621881656 has 64 divisors (see below), whose sum is σ = 57738304915200. Its totient is φ = 6816939683328.

The previous prime is 21770621881597. The next prime is 21770621881703. The reversal of 21770621881656 is 65618812607712.

It is a super-2 number, since 2×21770621881656² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21770621881656.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 50799396 + ... + 51226163.

It is an arithmetic number, because the mean of its divisors is an integer number (902161014300).

Almost surely, 2^{21770621881656} is an apocalyptic number.

It is an amenable number.

21770621881656 is an abundant number, since it is smaller than the sum of its proper divisors (35967683033544).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21770621881656 is a wasteful number, since it uses less digits than its factorization.

21770621881656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102026108 (or 102026104 counting only the distinct ones).

The product of its (nonzero) digits is 13547520, while the sum is 60.

The spelling of 21770621881656 in words is "twenty-one trillion, seven hundred seventy billion, six hundred twenty-one million, eight hundred eighty-one thousand, six hundred fifty-six".