21275660 has 24 divisors (see below), whose sum is σ = 51061920. Its totient is φ = 7294464.

The previous prime is 21275659. The next prime is 21275671. The reversal of 21275660 is 6657212.

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, 75845 + ... + 76124.

It is an arithmetic number, because the mean of its divisors is an integer number (2127580).

Almost surely, 2^21275660 is an apocalyptic number.

21275660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21275660 is an abundant number, since it is smaller than the sum of its proper divisors (29786260).

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

21275660 is a wasteful number, since it uses less digits than its factorization.

21275660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151985 (or 151983 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 29.

The square root of 21275660 is about 4612.5546067228. The cubic root of 21275660 is about 277.0943563306.

The spelling of 21275660 in words is "twenty-one million, two hundred seventy-five thousand, six hundred sixty".