189817421 has 8 divisors (see below), whose sum is σ = 193299384. Its totient is φ = 186347520.

The previous prime is 189817417. The next prime is 189817423. The reversal of 189817421 is 124718981.

It can be written as a sum of positive squares in 4 ways, for example, as 83521321 + 106296100 = 9139^2 + 10310^2 .

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 189817421 - 2² = 189817417 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (189817423) 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, 32501 + ... + 37893.

It is an arithmetic number, because the mean of its divisors is an integer number (24162423).

Almost surely, 2^189817421 is an apocalyptic number.

It is an amenable number.

189817421 is a deficient number, since it is larger than the sum of its proper divisors (3481963).

189817421 is an equidigital number, since it uses as much as digits as its factorization.

189817421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6031.

The product of its digits is 32256, while the sum is 41.

The square root of 189817421 is about 13777.4243238713. The cubic root of 189817421 is about 574.7055036366.

The spelling of 189817421 in words is "one hundred eighty-nine million, eight hundred seventeen thousand, four hundred twenty-one".