661396264452 has 432 divisors, whose sum is σ = 2330415360000. Its totient is φ = 155671528320.

The previous prime is 661396264447. The next prime is 661396264517. The reversal of 661396264452 is 254462693166.

661396264452 is a `hidden beast` number, since 6 + 6 + 1 + 3 + 9 + 626 + 4 + 4 + 5 + 2 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 8440549 + ... + 8518547.

It is an arithmetic number, because the mean of its divisors is an integer number (5394480000).

Almost surely, 2^661396264452 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 661396264452, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1165207680000).

661396264452 is an abundant number, since it is smaller than the sum of its proper divisors (1669019095548).

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

661396264452 is a wasteful number, since it uses less digits than its factorization.

661396264452 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78076 (or 78064 counting only the distinct ones).

The product of its digits is 11197440, while the sum is 54.

The spelling of 661396264452 in words is "six hundred sixty-one billion, three hundred ninety-six million, two hundred sixty-four thousand, four hundred fifty-two".