20642407785 has 144 divisors (see below), whose sum is σ = 40012315200. Its totient is φ = 9826354944.

The previous prime is 20642407771. The next prime is 20642407787. The reversal of 20642407785 is 58770424602.

It is a happy number.

It is not a de Polignac number, because 20642407785 - 2⁴ = 20642407769 is a prime.

It is a super-2 number, since 2×20642407785² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 20642407785.

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 143 ways as a sum of consecutive naturals, for example, 20257006 + ... + 20258024.

It is an arithmetic number, because the mean of its divisors is an integer number (277863300).

Almost surely, 2^20642407785 is an apocalyptic number.

It is an amenable number.

20642407785 is a deficient number, since it is larger than the sum of its proper divisors (19369907415).

20642407785 is a wasteful number, since it uses less digits than its factorization.

20642407785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1140 (or 1118 counting only the distinct ones).

The product of its (nonzero) digits is 752640, while the sum is 45.

The spelling of 20642407785 in words is "twenty billion, six hundred forty-two million, four hundred seven thousand, seven hundred eighty-five".