145105921 has 4 divisors (see below), whose sum is σ = 145204992. Its totient is φ = 145006852.

The previous prime is 145105913. The next prime is 145105963. The reversal of 145105921 is 129501541.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 129501541 = 13 ⋅9961657.

It is a cyclic number.

It is not a de Polignac number, because 145105921 - 2³ = 145105913 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 145105921.

It is not an unprimeable number, because it can be changed into a prime (145105901) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47305 + ... + 50278.

It is an arithmetic number, because the mean of its divisors is an integer number (36301248).

Almost surely, 2^145105921 is an apocalyptic number.

It is an amenable number.

145105921 is a deficient number, since it is larger than the sum of its proper divisors (99071).

145105921 is an equidigital number, since it uses as much as digits as its factorization.

145105921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99070.

The product of its (nonzero) digits is 1800, while the sum is 28.

The square root of 145105921 is about 12045.9919060242. The cubic root of 145105921 is about 525.4866791662.

The spelling of 145105921 in words is "one hundred forty-five million, one hundred five thousand, nine hundred twenty-one".