64821551 has 8 divisors (see below), whose sum is σ = 65729664. Its totient is φ = 63919960.

The previous prime is 64821541. The next prime is 64821553. The reversal of 64821551 is 15512846.

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

It is a cyclic number.

It is not a de Polignac number, because 64821551 - 2⁶ = 64821487 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 (64821553) 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, 20396 + ... + 23358.

It is an arithmetic number, because the mean of its divisors is an integer number (8216208).

Almost surely, 2^64821551 is an apocalyptic number.

64821551 is a deficient number, since it is larger than the sum of its proper divisors (908113).

64821551 is a wasteful number, since it uses less digits than its factorization.

64821551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3261.

The product of its digits is 9600, while the sum is 32.

The square root of 64821551 is about 8051.1832049706. The cubic root of 64821551 is about 401.7042927359.

The spelling of 64821551 in words is "sixty-four million, eight hundred twenty-one thousand, five hundred fifty-one".