102640666 has 4 divisors (see below), whose sum is σ = 153961002. Its totient is φ = 51320332.

The previous prime is 102640661. The next prime is 102640673. The reversal of 102640666 is 666046201.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 666046201 = 3079 ⋅216319.

It can be written as a sum of positive squares in only one way, i.e., 70207641 + 32433025 = 8379^2 + 5695^2 .

It is not an unprimeable number, because it can be changed into a prime (102640661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25660165 + ... + 25660168.

Almost surely, 2^102640666 is an apocalyptic number.

102640666 is a deficient number, since it is larger than the sum of its proper divisors (51320336).

102640666 is an equidigital number, since it uses as much as digits as its factorization.

102640666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51320335.

The product of its (nonzero) digits is 10368, while the sum is 31.

The square root of 102640666 is about 10131.1729824340. The cubic root of 102640666 is about 468.2090678387.

Adding to 102640666 its reverse (666046201), we get a palindrome (768686867).

The spelling of 102640666 in words is "one hundred two million, six hundred forty thousand, six hundred sixty-six".