21101666400 has 180 divisors, whose sum is σ = 76953910572. Its totient is φ = 5627093760.

The previous prime is 21101666393. The next prime is 21101666423. The reversal of 21101666400 is 466610112.

It is a tau number, because it is divible by the number of its divisors (180).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 98022 + ... + 227621.

Almost surely, 2^21101666400 is an apocalyptic number.

21101666400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21101666400 is an abundant number, since it is smaller than the sum of its proper divisors (55852244172).

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

21101666400 is a wasteful number, since it uses less digits than its factorization.

21101666400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 325675 (or 325653 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The spelling of 21101666400 in words is "twenty-one billion, one hundred one million, six hundred sixty-six thousand, four hundred".