20615540 has 48 divisors (see below), whose sum is σ = 47839680. Its totient is φ = 7399680.

The previous prime is 20615537. The next prime is 20615591. The reversal of 20615540 is 4551602.

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, 17696 + ... + 18824.

It is an arithmetic number, because the mean of its divisors is an integer number (996660).

Almost surely, 2^20615540 is an apocalyptic number.

20615540 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 20615540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23919840).

20615540 is an abundant number, since it is smaller than the sum of its proper divisors (27224140).

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

20615540 is a wasteful number, since it uses less digits than its factorization.

20615540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1232 (or 1230 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 20615540 is about 4540.4338999704. The cubic root of 20615540 is about 274.1983929106.

The spelling of 20615540 in words is "twenty million, six hundred fifteen thousand, five hundred forty".