661340694800 has 120 divisors (see below), whose sum is σ = 1660888458240. Its totient is φ = 252761932800.

The previous prime is 661340694793. The next prime is 661340694803. The reversal of 661340694800 is 8496043166.

661340694800 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (661340694803) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 642044 + ... + 1317156.

It is an arithmetic number, because the mean of its divisors is an integer number (13840737152).

Almost surely, 2^661340694800 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661340694800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (830444229120).

661340694800 is an abundant number, since it is smaller than the sum of its proper divisors (999547763440).

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

661340694800 is a wasteful number, since it uses less digits than its factorization.

661340694800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 675241 (or 675230 counting only the distinct ones).

The product of its (nonzero) digits is 746496, while the sum is 47.

The spelling of 661340694800 in words is "six hundred sixty-one billion, three hundred forty million, six hundred ninety-four thousand, eight hundred".