21643100639 has 8 divisors (see below), whose sum is σ = 22923512640. Its totient is φ = 20363498496.

The previous prime is 21643100581. The next prime is 21643100657. The reversal of 21643100639 is 93600134612.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21643100639 - 2³² = 17348133343 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21643100599 and 21643100608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21643100239) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 146999 + ... + 254744.

It is an arithmetic number, because the mean of its divisors is an integer number (2865439080).

Almost surely, 2^21643100639 is an apocalyptic number.

21643100639 is a deficient number, since it is larger than the sum of its proper divisors (1280412001).

21643100639 is a wasteful number, since it uses less digits than its factorization.

21643100639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 404929.

The product of its (nonzero) digits is 23328, while the sum is 35.

The spelling of 21643100639 in words is "twenty-one billion, six hundred forty-three million, one hundred thousand, six hundred thirty-nine".