665611451 has 4 divisors (see below), whose sum is σ = 688563600. Its totient is φ = 642659304.

The previous prime is 665611423. The next prime is 665611469. The reversal of 665611451 is 154116566.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 154116566 = 2 ⋅77058283.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-665611451 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665611481) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11476031 + ... + 11476088.

It is an arithmetic number, because the mean of its divisors is an integer number (172140900).

Almost surely, 2^665611451 is an apocalyptic number.

665611451 is a deficient number, since it is larger than the sum of its proper divisors (22952149).

665611451 is a wasteful number, since it uses less digits than its factorization.

665611451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22952148.

The product of its digits is 21600, while the sum is 35.

The square root of 665611451 is about 25799.4467188736. The cubic root of 665611451 is about 873.1193134474.

The spelling of 665611451 in words is "six hundred sixty-five million, six hundred eleven thousand, four hundred fifty-one".