66661519 has 4 divisors (see below), whose sum is σ = 70170040. Its totient is φ = 63153000.

The previous prime is 66661489. The next prime is 66661537. The reversal of 66661519 is 91516666.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66661519 - 2⁵ = 66661487 is a prime.

It is a super-2 number, since 2×66661519² = 8887516230774722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66661549) 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, 1754232 + ... + 1754269.

It is an arithmetic number, because the mean of its divisors is an integer number (17542510).

Almost surely, 2^66661519 is an apocalyptic number.

66661519 is a deficient number, since it is larger than the sum of its proper divisors (3508521).

66661519 is a wasteful number, since it uses less digits than its factorization.

66661519 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3508520.

The product of its digits is 58320, while the sum is 40.

The square root of 66661519 is about 8164.6505742744. The cubic root of 66661519 is about 405.4696963868.

The spelling of 66661519 in words is "sixty-six million, six hundred sixty-one thousand, five hundred nineteen".