20858717618 has 32 divisors (see below), whose sum is σ = 32914135296. Its totient is φ = 9894950208.

The previous prime is 20858717609. The next prime is 20858717623. The reversal of 20858717618 is 81671785802.

It is a super-2 number, since 2×20858717618² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20858717618.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4713755 + ... + 4718177.

It is an arithmetic number, because the mean of its divisors is an integer number (1028566728).

Almost surely, 2^20858717618 is an apocalyptic number.

20858717618 is a deficient number, since it is larger than the sum of its proper divisors (12055417678).

20858717618 is a wasteful number, since it uses less digits than its factorization.

20858717618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5258.

The product of its (nonzero) digits is 1505280, while the sum is 53.

The spelling of 20858717618 in words is "twenty billion, eight hundred fifty-eight million, seven hundred seventeen thousand, six hundred eighteen".