20615913 has 12 divisors (see below), whose sum is σ = 29912688. Its totient is φ = 13682040.

The previous prime is 20615911. The next prime is 20615923. The reversal of 20615913 is 31951602.

It is not a de Polignac number, because 20615913 - 2¹ = 20615911 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20615911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3003 + ... + 7088.

It is an arithmetic number, because the mean of its divisors is an integer number (2492724).

Almost surely, 2^20615913 is an apocalyptic number.

It is an amenable number.

20615913 is a deficient number, since it is larger than the sum of its proper divisors (9296775).

20615913 is a wasteful number, since it uses less digits than its factorization.

20615913 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10324 (or 10321 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 27.

The square root of 20615913 is about 4540.4749751540. The cubic root of 20615913 is about 274.2000466046.

It can be divided in two parts, 20615 and 913, that added together give a triangular number (21528 = T₂₀₇).

The spelling of 20615913 in words is "twenty million, six hundred fifteen thousand, nine hundred thirteen".