20403640 has 32 divisors (see below), whose sum is σ = 46889280. Its totient is φ = 7987072.

The previous prime is 20403589. The next prime is 20403709. The reversal of 20403640 is 4630402.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3547 + ... + 7306.

It is an arithmetic number, because the mean of its divisors is an integer number (1465290).

Almost surely, 2^20403640 is an apocalyptic number.

20403640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20403640 is an abundant number, since it is smaller than the sum of its proper divisors (26485640).

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

20403640 is a wasteful number, since it uses less digits than its factorization.

20403640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10911 (or 10907 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 19.

The square root of 20403640 is about 4517.0388530541. The cubic root of 20403640 is about 273.2556921392.

The spelling of 20403640 in words is "twenty million, four hundred three thousand, six hundred forty".