21903453921 has 8 divisors (see below), whose sum is σ = 29615937984. Its totient is φ = 14396636240.

The previous prime is 21903453919. The next prime is 21903453931. The reversal of 21903453921 is 12935430912.

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 21903453921 - 2¹ = 21903453919 is a prime.

It is a super-2 number, since 2×21903453921² (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 21903453921.

It is not an unprimeable number, because it can be changed into a prime (21903453911) 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, 51416346 + ... + 51416771.

It is an arithmetic number, because the mean of its divisors is an integer number (3701992248).

Almost surely, 2^21903453921 is an apocalyptic number.

It is an amenable number.

21903453921 is a deficient number, since it is larger than the sum of its proper divisors (7712484063).

21903453921 is a wasteful number, since it uses less digits than its factorization.

21903453921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102833191.

The product of its (nonzero) digits is 58320, while the sum is 39.

The spelling of 21903453921 in words is "twenty-one billion, nine hundred three million, four hundred fifty-three thousand, nine hundred twenty-one".