2638640 has 20 divisors (see below), whose sum is σ = 6135024. Its totient is φ = 1055424.

The previous prime is 2638633. The next prime is 2638651. The reversal of 2638640 is 468362.

It is a tau number, because it is divible by the number of its divisors (20).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16412 + ... + 16571.

2^2638640 is an apocalyptic number.

2638640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2638640 is an abundant number, since it is smaller than the sum of its proper divisors (3496384).

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

2638640 is a wasteful number, since it uses less digits than its factorization.

2638640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32996 (or 32990 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 29.

The square root of 2638640 is about 1624.3891159448. The cubic root of 2638640 is about 138.1847277571.

The spelling of 2638640 in words is "two million, six hundred thirty-eight thousand, six hundred forty".