20511517308 has 24 divisors (see below), whose sum is σ = 48225555840. Its totient is φ = 6784979760.

The previous prime is 20511517259. The next prime is 20511517339. The reversal of 20511517308 is 80371511502.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6522448 + ... + 6525591.

It is an arithmetic number, because the mean of its divisors is an integer number (2009398160).

Almost surely, 2^20511517308 is an apocalyptic number.

It is an amenable number.

20511517308 is an abundant number, since it is smaller than the sum of its proper divisors (27714038532).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20511517308 is a wasteful number, since it uses less digits than its factorization.

20511517308 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13048177 (or 13048175 counting only the distinct ones).

The product of its (nonzero) digits is 8400, while the sum is 33.

The spelling of 20511517308 in words is "twenty billion, five hundred eleven million, five hundred seventeen thousand, three hundred eight".