21739240636 has 12 divisors (see below), whose sum is σ = 38059612360. Its totient is φ = 10865065680.

The previous prime is 21739240613. The next prime is 21739240643. The reversal of 21739240636 is 63604293712.

It is a junction number, because it is equal to n+sod(n) for n = 21739240592 and 21739240601.

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 3 ways as a sum of consecutive naturals, for example, 1127910 + ... + 1147021.

Almost surely, 2^21739240636 is an apocalyptic number.

It is an amenable number.

21739240636 is a deficient number, since it is larger than the sum of its proper divisors (16320371724).

21739240636 is a wasteful number, since it uses less digits than its factorization.

21739240636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2277324 (or 2277322 counting only the distinct ones).

The product of its (nonzero) digits is 326592, while the sum is 43.

The spelling of 21739240636 in words is "twenty-one billion, seven hundred thirty-nine million, two hundred forty thousand, six hundred thirty-six".