20897940 has 48 divisors (see below), whose sum is σ = 66874752. Its totient is φ = 4776576.

The previous prime is 20897923. The next prime is 20897969. The reversal of 20897940 is 4979802.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24459 + ... + 25298.

It is an arithmetic number, because the mean of its divisors is an integer number (1393224).

Almost surely, 2^20897940 is an apocalyptic number.

20897940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20897940 is an abundant number, since it is smaller than the sum of its proper divisors (45976812).

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

20897940 is a wasteful number, since it uses less digits than its factorization.

20897940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49776 (or 49774 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 39.

The square root of 20897940 is about 4571.4264732138. The cubic root of 20897940 is about 275.4447459082. Note that the first 3 decimals are identical.

The spelling of 20897940 in words is "twenty million, eight hundred ninety-seven thousand, nine hundred forty".