661503998 has 16 divisors (see below), whose sum is σ = 1009098240. Its totient is φ = 325157976.

The previous prime is 661503979. The next prime is 661504003. The reversal of 661503998 is 899305166.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 65363 + ... + 74801.

It is an arithmetic number, because the mean of its divisors is an integer number (63068640).

Almost surely, 2^661503998 is an apocalyptic number.

661503998 is a deficient number, since it is larger than the sum of its proper divisors (347594242).

661503998 is a wasteful number, since it uses less digits than its factorization.

661503998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10031.

The product of its (nonzero) digits is 349920, while the sum is 47.

The square root of 661503998 is about 25719.7200218043. The cubic root of 661503998 is about 871.3196153995.

The spelling of 661503998 in words is "six hundred sixty-one million, five hundred three thousand, nine hundred ninety-eight".