21896749 has 4 divisors (see below), whose sum is σ = 25024864. Its totient is φ = 18768636.

The previous prime is 21896717. The next prime is 21896767. The reversal of 21896749 is 94769812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21896749 - 2⁵ = 21896717 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21896699 and 21896708.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21896779) 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, 1564047 + ... + 1564060.

It is an arithmetic number, because the mean of its divisors is an integer number (6256216).

Almost surely, 2^21896749 is an apocalyptic number.

It is an amenable number.

21896749 is a deficient number, since it is larger than the sum of its proper divisors (3128115).

21896749 is an equidigital number, since it uses as much as digits as its factorization.

21896749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3128114.

The product of its digits is 217728, while the sum is 46.

The square root of 21896749 is about 4679.3962217363. The cubic root of 21896749 is about 279.7648919274.

The spelling of 21896749 in words is "twenty-one million, eight hundred ninety-six thousand, seven hundred forty-nine".