20615264261 has 4 divisors (see below), whose sum is σ = 20628046572. Its totient is φ = 20602481952.

The previous prime is 20615264239. The next prime is 20615264269. The reversal of 20615264261 is 16246251602.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15359884225 + 5255380036 = 123935^2 + 72494^2 .

It is a cyclic number.

It is not a de Polignac number, because 20615264261 - 2²² = 20611069957 is a prime.

It is a super-2 number, since 2×20615264261² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20615264269) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6388736 + ... + 6391961.

It is an arithmetic number, because the mean of its divisors is an integer number (5157011643).

Almost surely, 2^20615264261 is an apocalyptic number.

It is an amenable number.

20615264261 is a deficient number, since it is larger than the sum of its proper divisors (12782311).

20615264261 is a wasteful number, since it uses less digits than its factorization.

20615264261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12782310.

The product of its (nonzero) digits is 34560, while the sum is 35.

The spelling of 20615264261 in words is "twenty billion, six hundred fifteen million, two hundred sixty-four thousand, two hundred sixty-one".