21890663424 has 440 divisors, whose sum is σ = 76802784960. Its totient is φ = 6079463424.

The previous prime is 21890663371. The next prime is 21890663429. The reversal of 21890663424 is 42436609812.

21890663424 is a `hidden beast` number, since 2 + 1 + 8 + 9 + 0 + 6 + 634 + 2 + 4 = 666.

It is a super-2 number, since 2×21890663424² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21890663424.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21890663429) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 21481987 + ... + 21483005.

It is an arithmetic number, because the mean of its divisors is an integer number (174551784).

Almost surely, 2^21890663424 is an apocalyptic number.

21890663424 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 21890663424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38401392480).

21890663424 is an abundant number, since it is smaller than the sum of its proper divisors (54912121536).

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

21890663424 is a wasteful number, since it uses less digits than its factorization.

21890663424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1095 (or 1068 counting only the distinct ones).

The product of its (nonzero) digits is 497664, while the sum is 45.

The spelling of 21890663424 in words is "twenty-one billion, eight hundred ninety million, six hundred sixty-three thousand, four hundred twenty-four".