21694207860 has 192 divisors, whose sum is σ = 72992156160. Its totient is φ = 5317539840.

The previous prime is 21694207813. The next prime is 21694207889. The reversal of 21694207860 is 6870249612.

It is a happy number.

21694207860 is a `hidden beast` number, since 2 + 169 + 420 + 7 + 8 + 60 = 666.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1685409 + ... + 1698231.

It is an arithmetic number, because the mean of its divisors is an integer number (380167480).

Almost surely, 2^21694207860 is an apocalyptic number.

21694207860 is a gapful number since it is divisible by the number (20) 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 21694207860, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36496078080).

21694207860 is an abundant number, since it is smaller than the sum of its proper divisors (51297948300).

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

21694207860 is a wasteful number, since it uses less digits than its factorization.

21694207860 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13095 (or 13087 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 45.

The spelling of 21694207860 in words is "twenty-one billion, six hundred ninety-four million, two hundred seven thousand, eight hundred sixty".