666521434 has 8 divisors (see below), whose sum is σ = 1000252980. Its totient is φ = 333103776.

The previous prime is 666521423. The next prime is 666521437. The reversal of 666521434 is 434125666.

It can be written as a sum of positive squares in 2 ways, for example, as 660747025 + 5774409 = 25705^2 + 2403^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 666521393 and 666521402.

It is not an unprimeable number, because it can be changed into a prime (666521437) 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, 73089 + ... + 81700.

Almost surely, 2^666521434 is an apocalyptic number.

666521434 is a deficient number, since it is larger than the sum of its proper divisors (333731546).

666521434 is a wasteful number, since it uses less digits than its factorization.

666521434 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156944.

The product of its digits is 103680, while the sum is 37.

The square root of 666521434 is about 25817.0764030322. The cubic root of 666521434 is about 873.5170239190.

It can be divided in two parts, 66652 and 1434, that added together give a palindrome (68086).

The spelling of 666521434 in words is "six hundred sixty-six million, five hundred twenty-one thousand, four hundred thirty-four".