21997425216 has 448 divisors, whose sum is σ = 68964779520. Its totient is φ = 6131220480.

The previous prime is 21997425133. The next prime is 21997425221. The reversal of 21997425216 is 61252479912.

It is a happy number.

It is a super-2 number, since 2×21997425216² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

Its product of digits (544320) is a multiple of the sum of its prime divisors (324).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 121532646 + ... + 121532826.

It is an arithmetic number, because the mean of its divisors is an integer number (153939240).

Almost surely, 2^21997425216 is an apocalyptic number.

21997425216 is a gapful number since it is divisible by the number (26) 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 21997425216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34482389760).

21997425216 is an abundant number, since it is smaller than the sum of its proper divisors (46967354304).

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

21997425216 is a wasteful number, since it uses less digits than its factorization.

21997425216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 334 (or 324 counting only the distinct ones).

The product of its digits is 544320, while the sum is 48.

The spelling of 21997425216 in words is "twenty-one billion, nine hundred ninety-seven million, four hundred twenty-five thousand, two hundred sixteen".