661168998 has 144 divisors (see below), whose sum is σ = 1771620864. Its totient is φ = 174493440.

The previous prime is 661168967. The next prime is 661169027. The reversal of 661168998 is 899861166.

661168998 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 2439603 + ... + 2439873.

Almost surely, 2^661168998 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661168998, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (885810432).

661168998 is an abundant number, since it is smaller than the sum of its proper divisors (1110451866).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661168998 is a wasteful number, since it uses less digits than its factorization.

661168998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 387 (or 367 counting only the distinct ones).

The product of its digits is 1119744, while the sum is 54.

The square root of 661168998 is about 25713.2066845036. The cubic root of 661168998 is about 871.1725055008.

The spelling of 661168998 in words is "six hundred sixty-one million, one hundred sixty-eight thousand, nine hundred ninety-eight".