664215551 has 32 divisors (see below), whose sum is σ = 753919488. Its totient is φ = 581898240.

The previous prime is 664215533. The next prime is 664215581. The reversal of 664215551 is 155512466.

It is a cyclic number.

It is not a de Polignac number, because 664215551 - 2¹⁰ = 664214527 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 (664215511) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3147836 + ... + 3148046.

It is an arithmetic number, because the mean of its divisors is an integer number (23559984).

Almost surely, 2^664215551 is an apocalyptic number.

664215551 is a deficient number, since it is larger than the sum of its proper divisors (89703937).

664215551 is a wasteful number, since it uses less digits than its factorization.

664215551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 431.

The product of its digits is 36000, while the sum is 35.

The square root of 664215551 is about 25772.3796146184. The cubic root of 664215551 is about 872.5085265571.

The spelling of 664215551 in words is "six hundred sixty-four million, two hundred fifteen thousand, five hundred fifty-one".