20642407780 has 24 divisors (see below), whose sum is σ = 43356713400. Its totient is φ = 8255504640.

The previous prime is 20642407771. The next prime is 20642407787. The reversal of 20642407780 is 8770424602.

It can be written as a sum of positive squares in 4 ways, for example, as 5830544164 + 14811863616 = 76358^2 + 121704^2 .

It is a super-2 number, since 2×20642407780² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20642407787) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28750 + ... + 205210.

It is an arithmetic number, because the mean of its divisors is an integer number (1806529725).

Almost surely, 2^20642407780 is an apocalyptic number.

20642407780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20642407780 is an abundant number, since it is smaller than the sum of its proper divisors (22714305620).

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

20642407780 is a wasteful number, since it uses less digits than its factorization.

20642407780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 182319 (or 182317 counting only the distinct ones).

The product of its (nonzero) digits is 150528, while the sum is 40.

The spelling of 20642407780 in words is "twenty billion, six hundred forty-two million, four hundred seven thousand, seven hundred eighty".