21637449946 has 8 divisors (see below), whose sum is σ = 37092771360. Its totient is φ = 9273192828.

The previous prime is 21637449943. The next prime is 21637449961. The reversal of 21637449946 is 64994473612.

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 (21637449943) 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, 772766056 + ... + 772766083.

It is an arithmetic number, because the mean of its divisors is an integer number (4636596420).

Almost surely, 2^21637449946 is an apocalyptic number.

21637449946 is a deficient number, since it is larger than the sum of its proper divisors (15455321414).

21637449946 is a wasteful number, since it uses less digits than its factorization.

21637449946 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1545532148.

The product of its digits is 7838208, while the sum is 55.

The spelling of 21637449946 in words is "twenty-one billion, six hundred thirty-seven million, four hundred forty-nine thousand, nine hundred forty-six".