20515664345 has 24 divisors (see below), whose sum is σ = 28652129352. Its totient is φ = 14042800640.

The previous prime is 20515664317. The next prime is 20515664353. The reversal of 20515664345 is 54346651502.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 320696464 + 20194967881 = 17908^2 + 142109^2 .

It is not a de Polignac number, because 20515664345 - 2⁸ = 20515664089 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 987074 + ... + 1007643.

It is an arithmetic number, because the mean of its divisors is an integer number (1193838723).

Almost surely, 2^20515664345 is an apocalyptic number.

It is an amenable number.

20515664345 is a deficient number, since it is larger than the sum of its proper divisors (8136465007).

20515664345 is a wasteful number, since it uses less digits than its factorization.

20515664345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1994761 (or 1994750 counting only the distinct ones).

The product of its (nonzero) digits is 432000, while the sum is 41.

The spelling of 20515664345 in words is "twenty billion, five hundred fifteen million, six hundred sixty-four thousand, three hundred forty-five".