20616399865 has 8 divisors (see below), whose sum is σ = 24760015560. Its totient is φ = 16479562752.

The previous prime is 20616399857. The next prime is 20616399883. The reversal of 20616399865 is 56899361602.

It can be written as a sum of positive squares in 4 ways, for example, as 435640384 + 20180759481 = 20872^2 + 142059^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 20616399865 - 2³ = 20616399857 is a prime.

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, 1687950 + ... + 1700119.

It is an arithmetic number, because the mean of its divisors is an integer number (3095001945).

Almost surely, 2^20616399865 is an apocalyptic number.

It is an amenable number.

20616399865 is a deficient number, since it is larger than the sum of its proper divisors (4143615695).

20616399865 is a wasteful number, since it uses less digits than its factorization.

20616399865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3389291.

The product of its (nonzero) digits is 4199040, while the sum is 55.

The spelling of 20616399865 in words is "twenty billion, six hundred sixteen million, three hundred ninety-nine thousand, eight hundred sixty-five".