661373400 has 96 divisors (see below), whose sum is σ = 2059868160. Its totient is φ = 175539840.

The previous prime is 661373399. The next prime is 661373429. The reversal of 661373400 is 4373166.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 131329 + ... + 136271.

It is an arithmetic number, because the mean of its divisors is an integer number (21456960).

Almost surely, 2^661373400 is an apocalyptic number.

661373400 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 661373400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1029934080).

661373400 is an abundant number, since it is smaller than the sum of its proper divisors (1398494760).

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

661373400 is a wasteful number, since it uses less digits than its factorization.

661373400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5185 (or 5176 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 30.

The square root of 661373400 is about 25717.1810274766. The cubic root of 661373400 is about 871.2622712823.

The spelling of 661373400 in words is "six hundred sixty-one million, three hundred seventy-three thousand, four hundred".