21002755100 has 36 divisors (see below), whose sum is σ = 46348465800. Its totient is φ = 8258708160.

The previous prime is 21002755093. The next prime is 21002755127. The reversal of 21002755100 is 155720012.

It is a happy number.

It is a super-2 number, since 2×21002755100² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

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, 1773995 + ... + 1785794.

Almost surely, 2^21002755100 is an apocalyptic number.

21002755100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21002755100 is an abundant number, since it is smaller than the sum of its proper divisors (25345710700).

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

21002755100 is a wasteful number, since it uses less digits than its factorization.

21002755100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3559862 (or 3559855 counting only the distinct ones).

The product of its (nonzero) digits is 700, while the sum is 23.

The spelling of 21002755100 in words is "twenty-one billion, two million, seven hundred fifty-five thousand, one hundred".