21121708 has 6 divisors (see below), whose sum is σ = 36962996. Its totient is φ = 10560852.

The previous prime is 21121699. The next prime is 21121739. The reversal of 21121708 is 80712112.

It is a super-2 number, since 2×21121708² = 892253097674528, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2640210 + ... + 2640217.

Almost surely, 2^21121708 is an apocalyptic number.

It is an amenable number.

21121708 is a deficient number, since it is larger than the sum of its proper divisors (15841288).

21121708 is a wasteful number, since it uses less digits than its factorization.

21121708 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5280431 (or 5280429 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 22.

The square root of 21121708 is about 4595.8359413713. The cubic root of 21121708 is about 276.4243803903.

The spelling of 21121708 in words is "twenty-one million, one hundred twenty-one thousand, seven hundred eight".