21394694784 has 256 divisors, whose sum is σ = 61566220800. Its totient is φ = 6568181760.

The previous prime is 21394694693. The next prime is 21394694791. The reversal of 21394694784 is 48749649312.

It is a hoax number, since the sum of its digits (57) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 21458574 + ... + 21459570.

It is an arithmetic number, because the mean of its divisors is an integer number (240493050).

Almost surely, 2^21394694784 is an apocalyptic number.

21394694784 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 21394694784, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30783110400).

21394694784 is an abundant number, since it is smaller than the sum of its proper divisors (40171526016).

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

21394694784 is a wasteful number, since it uses less digits than its factorization.

21394694784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1131 (or 1119 counting only the distinct ones).

The product of its digits is 10450944, while the sum is 57.

The spelling of 21394694784 in words is "twenty-one billion, three hundred ninety-four million, six hundred ninety-four thousand, seven hundred eighty-four".