66991027 has 8 divisors (see below), whose sum is σ = 68553216. Its totient is φ = 65434632.

The previous prime is 66991021. The next prime is 66991037. The reversal of 66991027 is 72019966.

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 66991027 - 2¹⁹ = 66466739 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66991021) 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, 29308 + ... + 31510.

It is an arithmetic number, because the mean of its divisors is an integer number (8569152).

Almost surely, 2^66991027 is an apocalyptic number.

66991027 is a deficient number, since it is larger than the sum of its proper divisors (1562189).

66991027 is a wasteful number, since it uses less digits than its factorization.

66991027 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2897.

The product of its (nonzero) digits is 40824, while the sum is 40.

The square root of 66991027 is about 8184.8046403075. The cubic root of 66991027 is about 406.1366777569.

The spelling of 66991027 in words is "sixty-six million, nine hundred ninety-one thousand, twenty-seven".