21317649 has 8 divisors (see below), whose sum is σ = 29028480. Its totient is φ = 13909296.

The previous prime is 21317627. The next prime is 21317651. The reversal of 21317649 is 94671312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21317649 - 2⁷ = 21317521 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21317669) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 75454 + ... + 75735.

It is an arithmetic number, because the mean of its divisors is an integer number (3628560).

Almost surely, 2^21317649 is an apocalyptic number.

It is an amenable number.

21317649 is a deficient number, since it is larger than the sum of its proper divisors (7710831).

21317649 is a wasteful number, since it uses less digits than its factorization.

21317649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151239.

The product of its digits is 9072, while the sum is 33.

The square root of 21317649 is about 4617.1039624423. The cubic root of 21317649 is about 277.2765248932.

The spelling of 21317649 in words is "twenty-one million, three hundred seventeen thousand, six hundred forty-nine".