249999866 has 4 divisors (see below), whose sum is σ = 374999802. Its totient is φ = 124999932.

The previous prime is 249999859. The next prime is 249999877. The reversal of 249999866 is 668999942.

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

It can be written as a sum of positive squares in only one way, i.e., 141110641 + 108889225 = 11879^2 + 10435^2 .

It is a junction number, because it is equal to n+sod(n) for n = 249999799 and 249999808.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 62499965 + ... + 62499968.

Almost surely, 2^249999866 is an apocalyptic number.

249999866 is a deficient number, since it is larger than the sum of its proper divisors (124999936).

249999866 is a wasteful number, since it uses less digits than its factorization.

249999866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124999935.

The product of its digits is 15116544, while the sum is 62.

The square root of 249999866 is about 15811.3840633893. The cubic root of 249999866 is about 629.9604123945.

The spelling of 249999866 in words is "two hundred forty-nine million, nine hundred ninety-nine thousand, eight hundred sixty-six".