21710899 has 4 divisors (see below), whose sum is σ = 24812464. Its totient is φ = 18609336.

The previous prime is 21710869. The next prime is 21710917. The reversal of 21710899 is 99801712.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21710899 - 2¹⁷ = 21579827 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21710809) 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 3 ways as a sum of consecutive naturals, for example, 1550772 + ... + 1550785.

It is an arithmetic number, because the mean of its divisors is an integer number (6203116).

Almost surely, 2^21710899 is an apocalyptic number.

21710899 is a deficient number, since it is larger than the sum of its proper divisors (3101565).

21710899 is an equidigital number, since it uses as much as digits as its factorization.

21710899 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3101564.

The product of its (nonzero) digits is 9072, while the sum is 37.

The square root of 21710899 is about 4659.4955735573. The cubic root of 21710899 is about 278.9711347603.

The spelling of 21710899 in words is "twenty-one million, seven hundred ten thousand, eight hundred ninety-nine".