21198713906 has 8 divisors (see below), whose sum is σ = 32030173980. Its totient is φ = 10521989248.

The previous prime is 21198713897. The next prime is 21198713927. The reversal of 21198713906 is 60931789112.

It can be written as a sum of positive squares in 2 ways, for example, as 18976440025 + 2222273881 = 137755^2 + 47141^2 .

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, 38683511 + ... + 38684058.

Almost surely, 2^21198713906 is an apocalyptic number.

21198713906 is a deficient number, since it is larger than the sum of its proper divisors (10831460074).

21198713906 is a wasteful number, since it uses less digits than its factorization.

21198713906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77367708.

The product of its (nonzero) digits is 163296, while the sum is 47.

The spelling of 21198713906 in words is "twenty-one billion, one hundred ninety-eight million, seven hundred thirteen thousand, nine hundred six".