21345923 has 2 divisors, whose sum is σ = 21345924. Its totient is φ = 21345922.

The previous prime is 21345901. The next prime is 21345959. The reversal of 21345923 is 32954312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21345923 - 2¹⁶ = 21280387 is a prime.

It is not a weakly prime, because it can be changed into another prime (21345983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10672961 + 10672962.

It is an arithmetic number, because the mean of its divisors is an integer number (10672962).

Almost surely, 2^21345923 is an apocalyptic number.

21345923 is a deficient number, since it is larger than the sum of its proper divisors (1).

21345923 is an equidigital number, since it uses as much as digits as its factorization.

21345923 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6480, while the sum is 29.

The square root of 21345923 is about 4620.1648238997. The cubic root of 21345923 is about 277.3990564324.

The spelling of 21345923 in words is "twenty-one million, three hundred forty-five thousand, nine hundred twenty-three".