661406882400 has 1152 divisors, whose sum is σ = 2776772275200. Its totient is φ = 150161817600.

The previous prime is 661406882359. The next prime is 661406882443. The reversal of 661406882400 is 4288604166.

661406882400 is a `hidden beast` number, since 6 + 614 + 0 + 6 + 8 + 8 + 24 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 1506621381 + ... + 1506621819.

It is an arithmetic number, because the mean of its divisors is an integer number (2410392600).

Almost surely, 2^661406882400 is an apocalyptic number.

661406882400 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 661406882400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1388386137600).

661406882400 is an abundant number, since it is smaller than the sum of its proper divisors (2115365392800).

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

661406882400 is a wasteful number, since it uses less digits than its factorization.

661406882400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 869 (or 850 counting only the distinct ones).

The product of its (nonzero) digits is 442368, while the sum is 45.

The spelling of 661406882400 in words is "six hundred sixty-one billion, four hundred six million, eight hundred eighty-two thousand, four hundred".