20640230385 has 16 divisors (see below), whose sum is σ = 34762493760. Its totient is φ = 10428747840.

The previous prime is 20640230363. The next prime is 20640230411. The reversal of 20640230385 is 58303204602.

It is a happy number.

It is not a de Polignac number, because 20640230385 - 2⁵ = 20640230353 is a prime.

It is a super-2 number, since 2×20640230385² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36210646 + ... + 36211215.

It is an arithmetic number, because the mean of its divisors is an integer number (2172655860).

Almost surely, 2^20640230385 is an apocalyptic number.

It is an amenable number.

20640230385 is a deficient number, since it is larger than the sum of its proper divisors (14122263375).

20640230385 is a wasteful number, since it uses less digits than its factorization.

20640230385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72421888.

The product of its (nonzero) digits is 34560, while the sum is 33.

Adding to 20640230385 its reverse (58303204602), we get a palindrome (78943434987).

The spelling of 20640230385 in words is "twenty billion, six hundred forty million, two hundred thirty thousand, three hundred eighty-five".