21712435 has 4 divisors (see below), whose sum is σ = 26054928. Its totient is φ = 17369944.

The previous prime is 21712423. The next prime is 21712469. The reversal of 21712435 is 53421712.

It is a happy number.

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 21712435 - 2¹⁵ = 21679667 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2171239 + ... + 2171248.

It is an arithmetic number, because the mean of its divisors is an integer number (6513732).

Almost surely, 2^21712435 is an apocalyptic number.

21712435 is a deficient number, since it is larger than the sum of its proper divisors (4342493).

21712435 is an equidigital number, since it uses as much as digits as its factorization.

21712435 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4342492.

The product of its digits is 1680, while the sum is 25.

The square root of 21712435 is about 4659.6603953507. The cubic root of 21712435 is about 278.9777134770.

Subtracting from 21712435 its product of digits (1680), we obtain a triangular number (21710755 = T₆₅₈₉).

The spelling of 21712435 in words is "twenty-one million, seven hundred twelve thousand, four hundred thirty-five".