2531216666 has 24 divisors (see below), whose sum is σ = 4418869140. Its totient is φ = 1082871680.

The previous prime is 2531216659. The next prime is 2531216687. The reversal of 2531216666 is 6666121352.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 2462243641 + 68973025 = 49621^2 + 8305^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 303521 + ... + 311748.

Almost surely, 2^2531216666 is an apocalyptic number.

2531216666 is a deficient number, since it is larger than the sum of its proper divisors (1887652474).

2531216666 is a wasteful number, since it uses less digits than its factorization.

2531216666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 615310 (or 615299 counting only the distinct ones).

The product of its digits is 77760, while the sum is 38.

The square root of 2531216666 is about 50311.1982166992. The cubic root of 2531216666 is about 1362.8344621882.

The spelling of 2531216666 in words is "two billion, five hundred thirty-one million, two hundred sixteen thousand, six hundred sixty-six".