145191921 has 16 divisors (see below), whose sum is σ = 221758464. Its totient is φ = 82774224.

The previous prime is 145191913. The next prime is 145191923. The reversal of 145191921 is 129191541.

It is not a de Polignac number, because 145191921 - 2³ = 145191913 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (145191923) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1500 + ... + 17106.

It is an arithmetic number, because the mean of its divisors is an integer number (13859904).

Almost surely, 2^145191921 is an apocalyptic number.

It is an amenable number.

145191921 is a deficient number, since it is larger than the sum of its proper divisors (76566543).

145191921 is a wasteful number, since it uses less digits than its factorization.

145191921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16060.

The product of its digits is 3240, while the sum is 33.

The square root of 145191921 is about 12049.5610293487. The cubic root of 145191921 is about 525.5904721497.

The spelling of 145191921 in words is "one hundred forty-five million, one hundred ninety-one thousand, nine hundred twenty-one".