21697435 has 4 divisors (see below), whose sum is σ = 26036928. Its totient is φ = 17357944.

The previous prime is 21697433. The next prime is 21697439. The reversal of 21697435 is 53479612.

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 21697435 - 2¹ = 21697433 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21697394 and 21697403.

It is not an unprimeable number, because it can be changed into a prime (21697433) by changing a digit.

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, 2169739 + ... + 2169748.

It is an arithmetic number, because the mean of its divisors is an integer number (6509232).

Almost surely, 2^21697435 is an apocalyptic number.

21697435 is a deficient number, since it is larger than the sum of its proper divisors (4339493).

21697435 is an equidigital number, since it uses as much as digits as its factorization.

21697435 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4339492.

The product of its digits is 45360, while the sum is 37.

The square root of 21697435 is about 4658.0505579051. The cubic root of 21697435 is about 278.9134549123.

It can be divided in two parts, 2169 and 7435, that added together give a square (9604 = 98²).

The spelling of 21697435 in words is "twenty-one million, six hundred ninety-seven thousand, four hundred thirty-five".