190724921 has 4 divisors (see below), whose sum is σ = 201944052. Its totient is φ = 179505792.

The previous prime is 190724879. The next prime is 190724923. The reversal of 190724921 is 129427091.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 129427091 = 3541 ⋅36551.

It can be written as a sum of positive squares in 2 ways, for example, as 169000000 + 21724921 = 13000^2 + 4661^2 .

It is a cyclic number.

It is not a de Polignac number, because 190724921 - 2¹⁸ = 190462777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (190724923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5609540 + ... + 5609573.

It is an arithmetic number, because the mean of its divisors is an integer number (50486013).

Almost surely, 2^190724921 is an apocalyptic number.

It is an amenable number.

190724921 is a deficient number, since it is larger than the sum of its proper divisors (11219131).

190724921 is a wasteful number, since it uses less digits than its factorization.

190724921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11219130.

The product of its (nonzero) digits is 9072, while the sum is 35.

The square root of 190724921 is about 13810.3193663289. The cubic root of 190724921 is about 575.6199196910.

The spelling of 190724921 in words is "one hundred ninety million, seven hundred twenty-four thousand, nine hundred twenty-one".