21649473973 has 16 divisors (see below), whose sum is σ = 23539507200. Its totient is φ = 19834004736.

The previous prime is 21649473953. The next prime is 21649474009. The reversal of 21649473973 is 37937494612.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21649473973 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21649473953) 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, 19828 + ... + 209026.

It is an arithmetic number, because the mean of its divisors is an integer number (1471219200).

Almost surely, 2^21649473973 is an apocalyptic number.

It is an amenable number.

21649473973 is a deficient number, since it is larger than the sum of its proper divisors (1890033227).

21649473973 is a wasteful number, since it uses less digits than its factorization.

21649473973 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 189396.

The product of its digits is 6858432, while the sum is 55.

The spelling of 21649473973 in words is "twenty-one billion, six hundred forty-nine million, four hundred seventy-three thousand, nine hundred seventy-three".