945181921 has 4 divisors (see below), whose sum is σ = 945475732. Its totient is φ = 944888112.

The previous prime is 945181907. The next prime is 945181927. The reversal of 945181921 is 129181549.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 129181549 = 7 ⋅18454507.

It can be written as a sum of positive squares in 2 ways, for example, as 943165521 + 2016400 = 30711^2 + 1420^2 .

It is a cyclic number.

It is not a de Polignac number, because 945181921 - 2²⁹ = 408311009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (945181927) 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, 142026 + ... + 148531.

It is an arithmetic number, because the mean of its divisors is an integer number (236368933).

Almost surely, 2^945181921 is an apocalyptic number.

It is an amenable number.

945181921 is a deficient number, since it is larger than the sum of its proper divisors (293811).

945181921 is a wasteful number, since it uses less digits than its factorization.

945181921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 293810.

The product of its digits is 25920, while the sum is 40.

The square root of 945181921 is about 30743.8111007728. The cubic root of 945181921 is about 981.3828599849.

The spelling of 945181921 in words is "nine hundred forty-five million, one hundred eighty-one thousand, nine hundred twenty-one".