20878440 has 64 divisors (see below), whose sum is σ = 68333760. Its totient is φ = 5061120.

The previous prime is 20878433. The next prime is 20878441. The reversal of 20878440 is 4487802.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (20878441) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6589 + ... + 9228.

It is an arithmetic number, because the mean of its divisors is an integer number (1067715).

Almost surely, 2^20878440 is an apocalyptic number.

20878440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20878440 is an abundant number, since it is smaller than the sum of its proper divisors (47455320).

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

20878440 is a wasteful number, since it uses less digits than its factorization.

20878440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15842 (or 15838 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 33.

The square root of 20878440 is about 4569.2931619672. The cubic root of 20878440 is about 275.3590461688.

The spelling of 20878440 in words is "twenty million, eight hundred seventy-eight thousand, four hundred forty".