20561513 has 8 divisors (see below), whose sum is σ = 23999232. Its totient is φ = 17248896.

The previous prime is 20561501. The next prime is 20561521. The reversal of 20561513 is 31516502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20561513 - 2⁸ = 20561257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20561533) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30920 + ... + 31577.

It is an arithmetic number, because the mean of its divisors is an integer number (2999904).

Almost surely, 2^20561513 is an apocalyptic number.

It is an amenable number.

20561513 is a deficient number, since it is larger than the sum of its proper divisors (3437719).

20561513 is an equidigital number, since it uses as much as digits as its factorization.

20561513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62551.

The product of its (nonzero) digits is 900, while the sum is 23.

The square root of 20561513 is about 4534.4804553554. The cubic root of 20561513 is about 273.9586534304.

The spelling of 20561513 in words is "twenty million, five hundred sixty-one thousand, five hundred thirteen".