20697720 has 64 divisors (see below), whose sum is σ = 62514720. Its totient is φ = 5481984.

The previous prime is 20697713. The next prime is 20697737. The reversal of 20697720 is 2779602.

It is a super-2 number, since 2×20697720² = 856791226396800, which contains 22 as substring.

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, 20262 + ... + 21258.

Almost surely, 2^20697720 is an apocalyptic number.

20697720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20697720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31257360).

20697720 is an abundant number, since it is smaller than the sum of its proper divisors (41817000).

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

20697720 is a wasteful number, since it uses less digits than its factorization.

20697720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1184 (or 1180 counting only the distinct ones).

The product of its (nonzero) digits is 10584, while the sum is 33.

The square root of 20697720 is about 4549.4746949511. The cubic root of 20697720 is about 274.5622567408.

The spelling of 20697720 in words is "twenty million, six hundred ninety-seven thousand, seven hundred twenty".