21715197386 has 4 divisors (see below), whose sum is σ = 32572796082. Its totient is φ = 10857598692.

The previous prime is 21715197307. The next prime is 21715197431. The reversal of 21715197386 is 68379151712.

It is a happy number.

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

It can be written as a sum of positive squares in only one way, i.e., 19266828025 + 2448369361 = 138805^2 + 49481^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5428799345 + ... + 5428799348.

Almost surely, 2^21715197386 is an apocalyptic number.

21715197386 is a deficient number, since it is larger than the sum of its proper divisors (10857598696).

21715197386 is a wasteful number, since it uses less digits than its factorization.

21715197386 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10857598695.

The product of its digits is 635040, while the sum is 50.

The spelling of 21715197386 in words is "twenty-one billion, seven hundred fifteen million, one hundred ninety-seven thousand, three hundred eighty-six".