666261421 has 8 divisors (see below), whose sum is σ = 761736960. Its totient is φ = 570859728.

The previous prime is 666261419. The next prime is 666261443. The reversal of 666261421 is 124162666.

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 666261421 - 2¹ = 666261419 is a prime.

It is a super-2 number, since 2×666261421² = 887808562225878482, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666261451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2460 + ... + 36586.

It is an arithmetic number, because the mean of its divisors is an integer number (95217120).

Almost surely, 2^666261421 is an apocalyptic number.

It is an amenable number.

666261421 is a deficient number, since it is larger than the sum of its proper divisors (95475539).

666261421 is a wasteful number, since it uses less digits than its factorization.

666261421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36923.

The product of its digits is 20736, while the sum is 34.

The square root of 666261421 is about 25812.0402331935. The cubic root of 666261421 is about 873.4034215095.

The spelling of 666261421 in words is "six hundred sixty-six million, two hundred sixty-one thousand, four hundred twenty-one".