145178021 has 4 divisors (see below), whose sum is σ = 145204044. Its totient is φ = 145152000.

The previous prime is 145178017. The next prime is 145178027. The reversal of 145178021 is 120871541.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 79405921 + 65772100 = 8911^2 + 8110^2 .

It is a cyclic number.

It is not a de Polignac number, because 145178021 - 2² = 145178017 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 (145178027) 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, 860 + ... + 17061.

It is an arithmetic number, because the mean of its divisors is an integer number (36301011).

Almost surely, 2^145178021 is an apocalyptic number.

It is an amenable number.

145178021 is a deficient number, since it is larger than the sum of its proper divisors (26023).

145178021 is an equidigital number, since it uses as much as digits as its factorization.

145178021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26022.

The product of its (nonzero) digits is 2240, while the sum is 29.

The square root of 145178021 is about 12048.9842310462. The cubic root of 145178021 is about 525.5736990844.

The spelling of 145178021 in words is "one hundred forty-five million, one hundred seventy-eight thousand, twenty-one".