21997494624 has 192 divisors, whose sum is σ = 70051516416. Its totient is φ = 5900304384.

The previous prime is 21997494583. The next prime is 21997494643. The reversal of 21997494624 is 42649479912.

It is a Smith number, since the sum of its digits (57) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4944369 + ... + 4948815.

It is an arithmetic number, because the mean of its divisors is an integer number (364851648).

Almost surely, 2^21997494624 is an apocalyptic number.

21997494624 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21997494624, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35025758208).

21997494624 is an abundant number, since it is smaller than the sum of its proper divisors (48054021792).

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

21997494624 is a wasteful number, since it uses less digits than its factorization.

21997494624 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4917 (or 4909 counting only the distinct ones).

The product of its digits is 7838208, while the sum is 57.

The spelling of 21997494624 in words is "twenty-one billion, nine hundred ninety-seven million, four hundred ninety-four thousand, six hundred twenty-four".