20537999664 has 160 divisors (see below), whose sum is σ = 67065707520. Its totient is φ = 5270178816.

The previous prime is 20537999623. The next prime is 20537999681. The reversal of 20537999664 is 46699973502.

It is a super-2 number, since 2×20537999664² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20537999598 and 20537999607.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 98077 + ... + 225155.

It is an arithmetic number, because the mean of its divisors is an integer number (419160672).

Almost surely, 2^20537999664 is an apocalyptic number.

20537999664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20537999664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33532853760).

20537999664 is an abundant number, since it is smaller than the sum of its proper divisors (46527707856).

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

20537999664 is a wasteful number, since it uses less digits than its factorization.

20537999664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127147 (or 127141 counting only the distinct ones).

The product of its (nonzero) digits is 22044960, while the sum is 60.

It can be divided in two parts, 20537 and 999664, that added together give a palindrome (1020201).

The spelling of 20537999664 in words is "twenty billion, five hundred thirty-seven million, nine hundred ninety-nine thousand, six hundred sixty-four".