661829077536 has 384 divisors, whose sum is σ = 2115419120640. Its totient is φ = 178561843200.

The previous prime is 661829077487. The next prime is 661829077577. The reversal of 661829077536 is 635770928166.

It is a self number, because there is not a number n which added to its sum of digits gives 661829077536.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 399413220 + ... + 399414876.

It is an arithmetic number, because the mean of its divisors is an integer number (5508903960).

Almost surely, 2^661829077536 is an apocalyptic number.

661829077536 is a gapful number since it is divisible by the number (66) 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 661829077536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1057709560320).

661829077536 is an abundant number, since it is smaller than the sum of its proper divisors (1453590043104).

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

661829077536 is a wasteful number, since it uses less digits than its factorization.

661829077536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2888 (or 2880 counting only the distinct ones).

The product of its (nonzero) digits is 22861440, while the sum is 60.

The spelling of 661829077536 in words is "six hundred sixty-one billion, eight hundred twenty-nine million, seventy-seven thousand, five hundred thirty-six".