20686772738 has 8 divisors (see below), whose sum is σ = 31063137660. Its totient is φ = 10332393520.

The previous prime is 20686772699. The next prime is 20686772741. The reversal of 20686772738 is 83727768602.

It can be written as a sum of positive squares in 2 ways, for example, as 19422045769 + 1264726969 = 139363^2 + 35563^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5494073 + ... + 5497836.

Almost surely, 2^20686772738 is an apocalyptic number.

20686772738 is a deficient number, since it is larger than the sum of its proper divisors (10376364922).

20686772738 is a wasteful number, since it uses less digits than its factorization.

20686772738 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10992852.

The product of its (nonzero) digits is 9483264, while the sum is 56.

The spelling of 20686772738 in words is "twenty billion, six hundred eighty-six million, seven hundred seventy-two thousand, seven hundred thirty-eight".