661008337920 has 792 divisors, whose sum is σ = 2681798674464. Its totient is φ = 150097231872.

The previous prime is 661008337901. The next prime is 661008337939. The reversal of 661008337920 is 29733800166.

661008337920 is a `hidden beast` number, since 6 + 610 + 0 + 8 + 3 + 3 + 7 + 9 + 20 = 666.

It is an interprime number because it is at equal distance from previous prime (661008337901) and next prime (661008337939).

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 377071764 + ... + 377073516.

Almost surely, 2^661008337920 is an apocalyptic number.

661008337920 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 661008337920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1340899337232).

661008337920 is an abundant number, since it is smaller than the sum of its proper divisors (2020790336544).

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

661008337920 is a wasteful number, since it uses less digits than its factorization.

661008337920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1965 (or 1937 counting only the distinct ones).

The product of its (nonzero) digits is 326592, while the sum is 45.

The spelling of 661008337920 in words is "six hundred sixty-one billion, eight million, three hundred thirty-seven thousand, nine hundred twenty".