20720428 has 12 divisors (see below), whose sum is σ = 36526392. Its totient is φ = 10284320.

The previous prime is 20720423. The next prime is 20720429. The reversal of 20720428 is 82402702.

It is a super-2 number, since 2×20720428² = 858672273006368, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20720423) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18358 + ... + 19453.

It is an arithmetic number, because the mean of its divisors is an integer number (3043866).

Almost surely, 2^20720428 is an apocalyptic number.

It is an amenable number.

20720428 is a deficient number, since it is larger than the sum of its proper divisors (15805964).

20720428 is a wasteful number, since it uses less digits than its factorization.

20720428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37952 (or 37950 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 25.

The square root of 20720428 is about 4551.9696835546. The cubic root of 20720428 is about 274.6626298094.

The spelling of 20720428 in words is "twenty million, seven hundred twenty thousand, four hundred twenty-eight".