20646447387 has 4 divisors (see below), whose sum is σ = 27528596520. Its totient is φ = 13764298256.

The previous prime is 20646447379. The next prime is 20646447397. The reversal of 20646447387 is 78374464602.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20646447387 - 2³ = 20646447379 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20646447397) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3441074562 + ... + 3441074567.

It is an arithmetic number, because the mean of its divisors is an integer number (6882149130).

Almost surely, 2^20646447387 is an apocalyptic number.

20646447387 is a deficient number, since it is larger than the sum of its proper divisors (6882149133).

20646447387 is an equidigital number, since it uses as much as digits as its factorization.

20646447387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6882149132.

The product of its (nonzero) digits is 5419008, while the sum is 51.

The spelling of 20646447387 in words is "twenty billion, six hundred forty-six million, four hundred forty-seven thousand, three hundred eighty-seven".