20720518 has 64 divisors (see below), whose sum is σ = 41827968. Its totient is φ = 7464960.

The previous prime is 20720459. The next prime is 20720519. The reversal of 20720518 is 81502702.

It is a junction number, because it is equal to n+sod(n) for n = 20720492 and 20720501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20720519) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 114388 + ... + 114568.

It is an arithmetic number, because the mean of its divisors is an integer number (653562).

Almost surely, 2^20720518 is an apocalyptic number.

20720518 is an abundant number, since it is smaller than the sum of its proper divisors (21107450).

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

20720518 is a wasteful number, since it uses less digits than its factorization.

20720518 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 257.

The product of its (nonzero) digits is 1120, while the sum is 25.

The square root of 20720518 is about 4551.9795693742. The cubic root of 20720518 is about 274.6630274782.

The spelling of 20720518 in words is "twenty million, seven hundred twenty thousand, five hundred eighteen".