20949640 has 16 divisors (see below), whose sum is σ = 47136780. Its totient is φ = 8379840.

The previous prime is 20949631. The next prime is 20949667. The reversal of 20949640 is 4694902.

It can be written as a sum of positive squares in 2 ways, for example, as 17859076 + 3090564 = 4226^2 + 1758^2 .

It is a super-2 number, since 2×20949640² = 877774832259200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20949596 and 20949605.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 261831 + ... + 261910.

Almost surely, 2^20949640 is an apocalyptic number.

20949640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20949640 is an abundant number, since it is smaller than the sum of its proper divisors (26187140).

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

20949640 is a wasteful number, since it uses less digits than its factorization.

20949640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 523752 (or 523748 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 34.

The square root of 20949640 is about 4577.0776703045. The cubic root of 20949640 is about 275.6717023476.

The spelling of 20949640 in words is "twenty million, nine hundred forty-nine thousand, six hundred forty".