20308978261 has 24 divisors (see below), whose sum is σ = 24764555520. Its totient is φ = 16492694400.

The previous prime is 20308978201. The next prime is 20308978273. The reversal of 20308978261 is 16287980302.

It is not a de Polignac number, because 20308978261 - 2²¹ = 20306881109 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 (20308978201) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 118576 + ... + 233833.

It is an arithmetic number, because the mean of its divisors is an integer number (1031856480).

Almost surely, 2^20308978261 is an apocalyptic number.

It is an amenable number.

20308978261 is a deficient number, since it is larger than the sum of its proper divisors (4455577259).

20308978261 is a wasteful number, since it uses less digits than its factorization.

20308978261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 352477 (or 352464 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 46.

The spelling of 20308978261 in words is "twenty billion, three hundred eight million, nine hundred seventy-eight thousand, two hundred sixty-one".