13920561 has 6 divisors (see below), whose sum is σ = 20107490. Its totient is φ = 9280368.

The previous prime is 13920541. The next prime is 13920587. The reversal of 13920561 is 16502931.

13920561 is a `hidden beast` number, since 13 + 92 + 0 + 561 = 666.

It can be written as a sum of positive squares in only one way, i.e., 8088336 + 5832225 = 2844^2 + 2415^2 .

It is not a de Polignac number, because 13920561 - 2¹⁰ = 13919537 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13920541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 773356 + ... + 773373.

Almost surely, 2^13920561 is an apocalyptic number.

It is an amenable number.

13920561 is a deficient number, since it is larger than the sum of its proper divisors (6186929).

13920561 is a wasteful number, since it uses less digits than its factorization.

13920561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1546735 (or 1546732 counting only the distinct ones).

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

The square root of 13920561 is about 3731.0268023696. The cubic root of 13920561 is about 240.5575060265.

The spelling of 13920561 in words is "thirteen million, nine hundred twenty thousand, five hundred sixty-one".