21156698938 has 8 divisors (see below), whose sum is σ = 32592752532. Its totient is φ = 10292448096.

The previous prime is 21156698933. The next prime is 21156698993. The reversal of 21156698938 is 83989665112.

It can be written as a sum of positive squares in 2 ways, for example, as 20095047049 + 1061651889 = 141757^2 + 32583^2 .

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

It is not an unprimeable number, because it can be changed into a prime (21156698933) 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, 142950595 + ... + 142950742.

Almost surely, 2^21156698938 is an apocalyptic number.

21156698938 is a deficient number, since it is larger than the sum of its proper divisors (11436053594).

21156698938 is a wasteful number, since it uses less digits than its factorization.

21156698938 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 285901376.

The product of its digits is 5598720, while the sum is 58.

The spelling of 21156698938 in words is "twenty-one billion, one hundred fifty-six million, six hundred ninety-eight thousand, nine hundred thirty-eight".