18965921 has 8 divisors (see below), whose sum is σ = 20461224. Its totient is φ = 17475840.

The previous prime is 18965909. The next prime is 18965929. The reversal of 18965921 is 12956981.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 130321 + 18835600 = 361^2 + 4340^2 .

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 18965921 - 2¹⁴ = 18949537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18965929) 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, 9785 + ... + 11561.

It is an arithmetic number, because the mean of its divisors is an integer number (2557653).

Almost surely, 2^18965921 is an apocalyptic number.

It is an amenable number.

18965921 is a deficient number, since it is larger than the sum of its proper divisors (1495303).

18965921 is a wasteful number, since it uses less digits than its factorization.

18965921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2611.

The product of its digits is 38880, while the sum is 41.

The square root of 18965921 is about 4354.9880596851. The cubic root of 18965921 is about 266.6805317444.

The spelling of 18965921 in words is "eighteen million, nine hundred sixty-five thousand, nine hundred twenty-one".