21148991736 has 64 divisors (see below), whose sum is σ = 53191987200. Its totient is φ = 7007134848.

The previous prime is 21148991701. The next prime is 21148991737. The reversal of 21148991736 is 63719984112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21148991737) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8315281 + ... + 8317823.

It is an arithmetic number, because the mean of its divisors is an integer number (831124800).

Almost surely, 2^21148991736 is an apocalyptic number.

It is an amenable number.

21148991736 is an abundant number, since it is smaller than the sum of its proper divisors (32042995464).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21148991736 is a wasteful number, since it uses less digits than its factorization.

21148991736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4508 (or 4504 counting only the distinct ones).

The product of its digits is 653184, while the sum is 51.

The spelling of 21148991736 in words is "twenty-one billion, one hundred forty-eight million, nine hundred ninety-one thousand, seven hundred thirty-six".