21391416584 has 8 divisors (see below), whose sum is σ = 40108906110. Its totient is φ = 10695708288.

The previous prime is 21391416583. The next prime is 21391416601. The reversal of 21391416584 is 48561419312.

It can be written as a sum of positive squares in only one way, i.e., 16174243684 + 5217172900 = 127178^2 + 72230^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (21391416583) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1336963529 + ... + 1336963544.

Almost surely, 2^21391416584 is an apocalyptic number.

It is an amenable number.

21391416584 is a deficient number, since it is larger than the sum of its proper divisors (18717489526).

21391416584 is a wasteful number, since it uses less digits than its factorization.

21391416584 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2673927079 (or 2673927075 counting only the distinct ones).

The product of its digits is 207360, while the sum is 44.

The spelling of 21391416584 in words is "twenty-one billion, three hundred ninety-one million, four hundred sixteen thousand, five hundred eighty-four".