20649690 has 36 divisors (see below), whose sum is σ = 53801514. Its totient is φ = 5495088.

The previous prime is 20649667. The next prime is 20649709. The reversal of 20649690 is 9694602.

20649690 is a `hidden beast` number, since 2 + 0 + 649 + 6 + 9 + 0 = 666.

It can be written as a sum of positive squares in only one way, i.e., 18584721 + 2064969 = 4311^2 + 1437^2 .

It is a super-2 number, since 2×20649690² = 852819394192200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 42871 + ... + 43349.

Almost surely, 2^20649690 is an apocalyptic number.

20649690 is an abundant number, since it is smaller than the sum of its proper divisors (33151824).

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

20649690 is an equidigital number, since it uses as much as digits as its factorization.

20649690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 971 (or 489 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 36.

The square root of 20649690 is about 4544.1929976620. The cubic root of 20649690 is about 274.3497141857.

The spelling of 20649690 in words is "twenty million, six hundred forty-nine thousand, six hundred ninety".