21753917906 has 8 divisors (see below), whose sum is σ = 37292430720. Its totient is φ = 9323107668.

The previous prime is 21753917869. The next prime is 21753917909. The reversal of 21753917906 is 60971935712.

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

It is not an unprimeable number, because it can be changed into a prime (21753917909) 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, 776925626 + ... + 776925653.

It is an arithmetic number, because the mean of its divisors is an integer number (4661553840).

Almost surely, 2^21753917906 is an apocalyptic number.

21753917906 is a deficient number, since it is larger than the sum of its proper divisors (15538512814).

21753917906 is a wasteful number, since it uses less digits than its factorization.

21753917906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1553851288.

The product of its (nonzero) digits is 714420, while the sum is 50.

The spelling of 21753917906 in words is "twenty-one billion, seven hundred fifty-three million, nine hundred seventeen thousand, nine hundred six".