20145230721 has 24 divisors (see below), whose sum is σ = 36278858304. Its totient is φ = 10465054560.

The previous prime is 20145230701. The next prime is 20145230737. The reversal of 20145230721 is 12703254102.

20145230721 is a `hidden beast` number, since 201 + 452 + 3 + 0 + 7 + 2 + 1 = 666.

It is not a de Polignac number, because 20145230721 - 2⁵ = 20145230689 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20145230701) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 14534106 + ... + 14535491.

It is an arithmetic number, because the mean of its divisors is an integer number (1511619096).

Almost surely, 2^20145230721 is an apocalyptic number.

20145230721 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20145230721 is a deficient number, since it is larger than the sum of its proper divisors (16133627583).

20145230721 is a wasteful number, since it uses less digits than its factorization.

20145230721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29069621 (or 29069618 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

Adding to 20145230721 its reverse (12703254102), we get a palindrome (32848484823).

The spelling of 20145230721 in words is "twenty billion, one hundred forty-five million, two hundred thirty thousand, seven hundred twenty-one".