21697790400 has 1008 divisors, whose sum is σ = 93172349088. Its totient is φ = 4718592000.

The previous prime is 21697790399. The next prime is 21697790423. The reversal of 21697790400 is 409779612.

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 pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 84427072 + ... + 84427328.

It is an arithmetic number, because the mean of its divisors is an integer number (92432886).

Almost surely, 2^21697790400 is an apocalyptic number.

21697790400 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 21697790400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46586174544).

21697790400 is an abundant number, since it is smaller than the sum of its proper divisors (71474558688).

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

21697790400 is a wasteful number, since it uses less digits than its factorization.

21697790400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 350 (or 332 counting only the distinct ones).

The product of its (nonzero) digits is 190512, while the sum is 45.

The spelling of 21697790400 in words is "twenty-one billion, six hundred ninety-seven million, seven hundred ninety thousand, four hundred".