20006405136 has 75 divisors (see below), whose sum is σ = 57919082221. Its totient is φ = 6667104384.

The previous prime is 20006405093. The next prime is 20006405173. The reversal of 20006405136 is 63150460002.

The square root of 20006405136 is 141444.

It is a perfect power (a square), and thus also a powerful number.

20006405136 is a `hidden beast` number, since 2 + 0 + 0 + 0 + 640 + 5 + 13 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 2834923536 + 17171481600 = 53244^2 + 131040^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 5090020 + ... + 5093948.

Almost surely, 2^20006405136 is an apocalyptic number.

20006405136 is the 141444-th square number.

It is an amenable number.

20006405136 is an abundant number, since it is smaller than the sum of its proper divisors (37912677085).

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

20006405136 is an frugal number, since it uses more digits than its factorization.

20006405136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7878 (or 3934 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

Adding to 20006405136 its reverse (63150460002), we get a palindrome (83156865138).

The spelling of 20006405136 in words is "twenty billion, six million, four hundred five thousand, one hundred thirty-six".