21388369464 has 720 divisors, whose sum is σ = 80905948200. Its totient is φ = 5245067520.

The previous prime is 21388369459. The next prime is 21388369543. The reversal of 21388369464 is 46496388312.

21388369464 is a `hidden beast` number, since 213 + 8 + 8 + 369 + 4 + 64 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 21388369464.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 179 ways as a sum of consecutive naturals, for example, 72997702 + ... + 72997994.

Almost surely, 2^21388369464 is an apocalyptic number.

21388369464 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 21388369464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40452974100).

21388369464 is an abundant number, since it is smaller than the sum of its proper divisors (59517578736).

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

21388369464 is a wasteful number, since it uses less digits than its factorization.

21388369464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 366 (or 335 counting only the distinct ones).

The product of its digits is 5971968, while the sum is 54.

The spelling of 21388369464 in words is "twenty-one billion, three hundred eighty-eight million, three hundred sixty-nine thousand, four hundred sixty-four".