21681797294 has 8 divisors (see below), whose sum is σ = 34234416840. Its totient is φ = 10270325016.

The previous prime is 21681797273. The next prime is 21681797299. The reversal of 21681797294 is 49279718612.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21681797299) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 285286769 + ... + 285286844.

It is an arithmetic number, because the mean of its divisors is an integer number (4279302105).

Almost surely, 2^21681797294 is an apocalyptic number.

21681797294 is a deficient number, since it is larger than the sum of its proper divisors (12552619546).

21681797294 is a wasteful number, since it uses less digits than its factorization.

21681797294 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 570573634.

The product of its digits is 3048192, while the sum is 56.

The spelling of 21681797294 in words is "twenty-one billion, six hundred eighty-one million, seven hundred ninety-seven thousand, two hundred ninety-four".