21930345 has 40 divisors (see below), whose sum is σ = 39665736. Its totient is φ = 11591424.

The previous prime is 21930329. The next prime is 21930347. The reversal of 21930345 is 54303912.

It can be written as a sum of positive squares in 4 ways, for example, as 944784 + 20985561 = 972^2 + 4581^2 .

It is not a de Polignac number, because 21930345 - 2⁴ = 21930329 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21930347) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 69909 + ... + 70221.

Almost surely, 2^21930345 is an apocalyptic number.

It is an amenable number.

21930345 is a deficient number, since it is larger than the sum of its proper divisors (17735391).

21930345 is a wasteful number, since it uses less digits than its factorization.

21930345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 503 (or 494 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 27.

The square root of 21930345 is about 4682.9846252150. The cubic root of 21930345 is about 279.9078991302.

The spelling of 21930345 in words is "twenty-one million, nine hundred thirty thousand, three hundred forty-five".