21364699644 has 240 divisors, whose sum is σ = 60105830400. Its totient is φ = 6597811584.

The previous prime is 21364699613. The next prime is 21364699661. The reversal of 21364699644 is 44699646312.

21364699644 is a `hidden beast` number, since 2 + 136 + 469 + 9 + 6 + 44 = 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 congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 95805717 + ... + 95805939.

It is an arithmetic number, because the mean of its divisors is an integer number (250440960).

Almost surely, 2^21364699644 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21364699644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30052915200).

21364699644 is an abundant number, since it is smaller than the sum of its proper divisors (38741130756).

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

21364699644 is a wasteful number, since it uses less digits than its factorization.

21364699644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 534 (or 523 counting only the distinct ones).

The product of its digits is 6718464, while the sum is 54.

The spelling of 21364699644 in words is "twenty-one billion, three hundred sixty-four million, six hundred ninety-nine thousand, six hundred forty-four".