21649465 has 8 divisors (see below), whose sum is σ = 26028288. Its totient is φ = 17286960.

The previous prime is 21649447. The next prime is 21649487. The reversal of 21649465 is 56494612.

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

It is not a de Polignac number, because 21649465 - 2¹⁵ = 21616697 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 (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 937 + ... + 6646.

It is an arithmetic number, because the mean of its divisors is an integer number (3253536).

Almost surely, 2^21649465 is an apocalyptic number.

It is an amenable number.

21649465 is a deficient number, since it is larger than the sum of its proper divisors (4378823).

21649465 is an equidigital number, since it uses as much as digits as its factorization.

21649465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8159.

The product of its digits is 51840, while the sum is 37.

The square root of 21649465 is about 4652.8985589630. The cubic root of 21649465 is about 278.7077570097.

The spelling of 21649465 in words is "twenty-one million, six hundred forty-nine thousand, four hundred sixty-five".