21299407 has 2 divisors, whose sum is σ = 21299408. Its totient is φ = 21299406.

The previous prime is 21299393. The next prime is 21299417. The reversal of 21299407 is 70499212.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21299407 - 2⁷ = 21299279 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21299417) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10649703 + 10649704.

It is an arithmetic number, because the mean of its divisors is an integer number (10649704).

Almost surely, 2^21299407 is an apocalyptic number.

21299407 is a deficient number, since it is larger than the sum of its proper divisors (1).

21299407 is an equidigital number, since it uses as much as digits as its factorization.

21299407 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9072, while the sum is 34.

The square root of 21299407 is about 4615.1280588950. The cubic root of 21299407 is about 277.1974117004.

The spelling of 21299407 in words is "twenty-one million, two hundred ninety-nine thousand, four hundred seven".