21923145 has 24 divisors (see below), whose sum is σ = 38208456. Its totient is φ = 11628288.

The previous prime is 21923119. The next prime is 21923147. The reversal of 21923145 is 54132912.

It can be written as a sum of positive squares in 4 ways, for example, as 10653696 + 11269449 = 3264^2 + 3357^2 .

It is not a de Polignac number, because 21923145 - 2⁸ = 21922889 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21923147) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7629 + ... + 10101.

It is an arithmetic number, because the mean of its divisors is an integer number (1592019).

Almost surely, 2^21923145 is an apocalyptic number.

It is an amenable number.

21923145 is a deficient number, since it is larger than the sum of its proper divisors (16285311).

21923145 is a wasteful number, since it uses less digits than its factorization.

21923145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2681 (or 2678 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 21923145 is about 4682.2158215956. The cubic root of 21923145 is about 279.8772633837.

The spelling of 21923145 in words is "twenty-one million, nine hundred twenty-three thousand, one hundred forty-five".