661494600 has 336 divisors, whose sum is σ = 2490400500. Its totient is φ = 162362880.

The previous prime is 661494593. The next prime is 661494601. The reversal of 661494600 is 6494166.

661494600 is a `hidden beast` number, since 6 + 6 + 1 + 49 + 4 + 600 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 192598884 + 468895716 = 13878^2 + 21654^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (661494601) by changing a digit.

It is a polite number, since it can be written in 83 ways as a sum of consecutive naturals, for example, 1895226 + ... + 1895574.

Almost surely, 2^661494600 is an apocalyptic number.

661494600 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661494600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1245200250).

661494600 is an abundant number, since it is smaller than the sum of its proper divisors (1828905900).

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

661494600 is a wasteful number, since it uses less digits than its factorization.

661494600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 396 (or 372 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The square root of 661494600 is about 25719.5373208773. The cubic root of 661494600 is about 871.3154890952.

The spelling of 661494600 in words is "six hundred sixty-one million, four hundred ninety-four thousand, six hundred".