21370649 has 16 divisors (see below), whose sum is σ = 24076800. Its totient is φ = 18849024.

The previous prime is 21370639. The next prime is 21370667. The reversal of 21370649 is 94607312.

It is a cyclic number.

It is not a de Polignac number, because 21370649 - 2⁴ = 21370633 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21370619) 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 15 ways as a sum of consecutive naturals, for example, 34904 + ... + 35510.

It is an arithmetic number, because the mean of its divisors is an integer number (1504800).

Almost surely, 2^21370649 is an apocalyptic number.

It is an amenable number.

21370649 is a deficient number, since it is larger than the sum of its proper divisors (2706151).

21370649 is a wasteful number, since it uses less digits than its factorization.

21370649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 752.

The product of its (nonzero) digits is 9072, while the sum is 32.

The square root of 21370649 is about 4622.8399280096. The cubic root of 21370649 is about 277.5061232856.

The spelling of 21370649 in words is "twenty-one million, three hundred seventy thousand, six hundred forty-nine".