21997029600 has 1728 divisors, whose sum is σ = 106673172480. Its totient is φ = 4255027200.

The previous prime is 21997029583. The next prime is 21997029611. The reversal of 21997029600 is 692079912.

21997029600 is a `hidden beast` number, since 2 + 19 + 9 + 7 + 0 + 29 + 600 = 666.

It is a super-2 number, since 2×21997029600² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 709581585 + ... + 709581615.

It is an arithmetic number, because the mean of its divisors is an integer number (61732160).

Almost surely, 2^21997029600 is an apocalyptic number.

21997029600 is a gapful number since it is divisible by the number (20) 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 21997029600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (53336586240).

21997029600 is an abundant number, since it is smaller than the sum of its proper divisors (84676142880).

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

21997029600 is a wasteful number, since it uses less digits than its factorization.

21997029600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 118 (or 80 counting only the distinct ones).

The product of its (nonzero) digits is 122472, while the sum is 45.

The spelling of 21997029600 in words is "twenty-one billion, nine hundred ninety-seven million, twenty-nine thousand, six hundred".