64821621 has 8 divisors (see below), whose sum is σ = 86477824. Its totient is φ = 43189920.

The previous prime is 64821619. The next prime is 64821623. The reversal of 64821621 is 12612846.

It is an interprime number because it is at equal distance from previous prime (64821619) and next prime (64821623).

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

It is not a de Polignac number, because 64821621 - 2¹ = 64821619 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64821623) 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, 1356 + ... + 11466.

It is an arithmetic number, because the mean of its divisors is an integer number (10809728).

Almost surely, 2^64821621 is an apocalyptic number.

It is an amenable number.

64821621 is a deficient number, since it is larger than the sum of its proper divisors (21656203).

64821621 is a wasteful number, since it uses less digits than its factorization.

64821621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12251.

The product of its digits is 4608, while the sum is 30.

The square root of 64821621 is about 8051.1875521565. The cubic root of 64821621 is about 401.7044373343.

The spelling of 64821621 in words is "sixty-four million, eight hundred twenty-one thousand, six hundred twenty-one".