21423371 has 2 divisors, whose sum is σ = 21423372. Its totient is φ = 21423370.

The previous prime is 21423359. The next prime is 21423377. The reversal of 21423371 is 17332412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21423371 - 2⁶ = 21423307 is a prime.

It is equal to p_1355018 and since 21423371 and 1355018 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (21423377) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10711685 + 10711686.

It is an arithmetic number, because the mean of its divisors is an integer number (10711686).

Almost surely, 2^21423371 is an apocalyptic number.

21423371 is a deficient number, since it is larger than the sum of its proper divisors (1).

21423371 is an equidigital number, since it uses as much as digits as its factorization.

21423371 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1008, while the sum is 23.

The square root of 21423371 is about 4628.5387542938. The cubic root of 21423371 is about 277.7341410506.

Adding to 21423371 its reverse (17332412), we get a palindrome (38755783).

The spelling of 21423371 in words is "twenty-one million, four hundred twenty-three thousand, three hundred seventy-one".