66291663 has 8 divisors (see below), whose sum is σ = 88466608. Its totient is φ = 44155584.

The previous prime is 66291661. The next prime is 66291683. The reversal of 66291663 is 36619266.

It is a happy number.

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

It is not a de Polignac number, because 66291663 - 2¹ = 66291661 is a prime.

It is a Duffinian number.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66291661) 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, 5470 + ... + 12747.

It is an arithmetic number, because the mean of its divisors is an integer number (11058326).

Almost surely, 2^66291663 is an apocalyptic number.

66291663 is a deficient number, since it is larger than the sum of its proper divisors (22174945).

66291663 is a wasteful number, since it uses less digits than its factorization.

66291663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19433.

The product of its digits is 69984, while the sum is 39.

The square root of 66291663 is about 8141.9692335454. The cubic root of 66291663 is about 404.7184203394.

The spelling of 66291663 in words is "sixty-six million, two hundred ninety-one thousand, six hundred sixty-three".