20720406 has 32 divisors (see below), whose sum is σ = 47496960. Its totient is φ = 5903136.

The previous prime is 20720363. The next prime is 20720417. The reversal of 20720406 is 60402702.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (21).

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, 25600 + ... + 26396.

It is an arithmetic number, because the mean of its divisors is an integer number (1484280).

Almost surely, 2^20720406 is an apocalyptic number.

20720406 is an abundant number, since it is smaller than the sum of its proper divisors (26776554).

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

20720406 is a wasteful number, since it uses less digits than its factorization.

20720406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1428.

The product of its (nonzero) digits is 672, while the sum is 21.

The square root of 20720406 is about 4551.9672670176. The cubic root of 20720406 is about 274.6625326013.

The spelling of 20720406 in words is "twenty million, seven hundred twenty thousand, four hundred six".