21089640777408 has 504 divisors, whose sum is σ = 71964345641760. Its totient is φ = 5886180679680.

The previous prime is 21089640777383. The next prime is 21089640777409. The reversal of 21089640777408 is 80477704698012.

21089640777408 is a `hidden beast` number, since 21 + 0 + 89 + 64 + 0 + 7 + 77 + 408 = 666.

It is a tau number, because it is divible by the number of its divisors (504).

It is a super-2 number, since 2×21089640777408² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (21089640777409) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 218377260 + ... + 218473812.

Almost surely, 2^{21089640777408} is an apocalyptic number.

21089640777408 is a gapful number since it is divisible by the number (28) 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 21089640777408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35982172820880).

21089640777408 is an abundant number, since it is smaller than the sum of its proper divisors (50874704864352).

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

21089640777408 is a wasteful number, since it uses less digits than its factorization.

21089640777408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96765 (or 96745 counting only the distinct ones).

The product of its (nonzero) digits is 37933056, while the sum is 63.

The spelling of 21089640777408 in words is "twenty-one trillion, eighty-nine billion, six hundred forty million, seven hundred seventy-seven thousand, four hundred eight".