21050247994 has 8 divisors (see below), whose sum is σ = 33432746868. Its totient is φ = 9905999040.

The previous prime is 21050247983. The next prime is 21050248001. The reversal of 21050247994 is 49974205012.

It can be written as a sum of positive squares in 2 ways, for example, as 17136119025 + 3914128969 = 130905^2 + 62563^2 .

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

It is a super-2 number, since 2×21050247994² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21050247994.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 309562437 + ... + 309562504.

Almost surely, 2^21050247994 is an apocalyptic number.

21050247994 is a deficient number, since it is larger than the sum of its proper divisors (12382498874).

21050247994 is a wasteful number, since it uses less digits than its factorization.

21050247994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 619124960.

The product of its (nonzero) digits is 181440, while the sum is 43.

The spelling of 21050247994 in words is "twenty-one billion, fifty million, two hundred forty-seven thousand, nine hundred ninety-four".