20120921765 has 16 divisors (see below), whose sum is σ = 27862318848. Its totient is φ = 13663247616.

The previous prime is 20120921753. The next prime is 20120921791. The reversal of 20120921765 is 56712902102.

It is a cyclic number.

It is not a de Polignac number, because 20120921765 - 2²² = 20116727461 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2787092 + ... + 2794301.

It is an arithmetic number, because the mean of its divisors is an integer number (1741394928).

Almost surely, 2^20120921765 is an apocalyptic number.

It is an amenable number.

20120921765 is a deficient number, since it is larger than the sum of its proper divisors (7741397083).

20120921765 is a wasteful number, since it uses less digits than its factorization.

20120921765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5581508.

The product of its (nonzero) digits is 15120, while the sum is 35.

The spelling of 20120921765 in words is "twenty billion, one hundred twenty million, nine hundred twenty-one thousand, seven hundred sixty-five".