21042850637 has 4 divisors (see below), whose sum is σ = 21043506816. Its totient is φ = 21042194460.

The previous prime is 21042850559. The next prime is 21042850651. The reversal of 21042850637 is 73605824012.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21042850637 - 2²⁴ = 21026073421 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21042850637.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21042850237) 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, 277373 + ... + 344994.

It is an arithmetic number, because the mean of its divisors is an integer number (5260876704).

Almost surely, 2^21042850637 is an apocalyptic number.

It is an amenable number.

21042850637 is a deficient number, since it is larger than the sum of its proper divisors (656179).

21042850637 is an equidigital number, since it uses as much as digits as its factorization.

21042850637 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 656178.

The product of its (nonzero) digits is 80640, while the sum is 38.

The spelling of 21042850637 in words is "twenty-one billion, forty-two million, eight hundred fifty thousand, six hundred thirty-seven".