661212300 has 144 divisors (see below), whose sum is σ = 2194359552. Its totient is φ = 150585600.

The previous prime is 661212283. The next prime is 661212301. The reversal of 661212300 is 3212166.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (661212301) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 967759 + ... + 968441.

It is an arithmetic number, because the mean of its divisors is an integer number (15238608).

Almost surely, 2^661212300 is an apocalyptic number.

661212300 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 661212300, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1097179776).

661212300 is an abundant number, since it is smaller than the sum of its proper divisors (1533147252).

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

661212300 is a wasteful number, since it uses less digits than its factorization.

661212300 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1168 (or 1161 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 661212300 is about 25714.0486893838. The cubic root of 661212300 is about 871.1915236784.

Adding to 661212300 its reverse (3212166), we get a palindrome (664424466).

The spelling of 661212300 in words is "six hundred sixty-one million, two hundred twelve thousand, three hundred".