21664266803600 has 60 divisors (see below), whose sum is σ = 52127143539540. Its totient is φ = 8652596620800.

The previous prime is 21664266803579. The next prime is 21664266803617. The reversal of 21664266803600 is 630866246612.

It can be written as a sum of positive squares in 6 ways, for example, as 3090338980096 + 18573927823504 = 1757936^2 + 4309748^2 .

It is a super-2 number, since 2×21664266803600² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (50).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 40704335 + ... + 41233134.

It is an arithmetic number, because the mean of its divisors is an integer number (868785725659).

Almost surely, 2^{21664266803600} is an apocalyptic number.

21664266803600 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21664266803600 is an abundant number, since it is smaller than the sum of its proper divisors (30462876735940).

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

21664266803600 is a wasteful number, since it uses less digits than its factorization.

21664266803600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81938148 (or 81938137 counting only the distinct ones).

The product of its (nonzero) digits is 2985984, while the sum is 50.

The spelling of 21664266803600 in words is "twenty-one trillion, six hundred sixty-four billion, two hundred sixty-six million, eight hundred three thousand, six hundred".