20499640 has 48 divisors (see below), whose sum is σ = 53659800. Its totient is φ = 7027776.

The previous prime is 20499571. The next prime is 20499659. The reversal of 20499640 is 4699402.

It is a junction number, because it is equal to n+sod(n) for n = 20499596 and 20499605.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3270 + ... + 7189.

Almost surely, 2^20499640 is an apocalyptic number.

20499640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20499640 is an abundant number, since it is smaller than the sum of its proper divisors (33160160).

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

20499640 is a wasteful number, since it uses less digits than its factorization.

20499640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10484 (or 10473 counting only the distinct ones).

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

The square root of 20499640 is about 4527.6528135448. The cubic root of 20499640 is about 273.6835816709.

The spelling of 20499640 in words is "twenty million, four hundred ninety-nine thousand, six hundred forty".