20638261789 has 4 divisors (see below), whose sum is σ = 20764877056. Its totient is φ = 20511646524.

The previous prime is 20638261769. The next prime is 20638261793. The reversal of 20638261789 is 98716283602.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20638261789 - 2¹⁷ = 20638130717 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20638261769) 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, 63307389 + ... + 63307714.

It is an arithmetic number, because the mean of its divisors is an integer number (5191219264).

Almost surely, 2^20638261789 is an apocalyptic number.

It is an amenable number.

20638261789 is a deficient number, since it is larger than the sum of its proper divisors (126615267).

20638261789 is a wasteful number, since it uses less digits than its factorization.

20638261789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126615266.

The product of its (nonzero) digits is 1741824, while the sum is 52.

The spelling of 20638261789 in words is "twenty billion, six hundred thirty-eight million, two hundred sixty-one thousand, seven hundred eighty-nine".