66011391720 has 128 divisors (see below), whose sum is σ = 223052457600. Its totient is φ = 17361879552.

The previous prime is 66011391713. The next prime is 66011391767. The reversal of 66011391720 is 2719311066.

66011391720 is a `hidden beast` number, since 6 + 601 + 1 + 39 + 17 + 2 + 0 = 666.

It is a super-2 number, since 2×66011391720² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 339802 + ... + 497481.

It is an arithmetic number, because the mean of its divisors is an integer number (1742597325).

Almost surely, 2^66011391720 is an apocalyptic number.

66011391720 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66011391720 is an abundant number, since it is smaller than the sum of its proper divisors (157041065880).

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

66011391720 is a wasteful number, since it uses less digits than its factorization.

66011391720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 837376 (or 837366 counting only the distinct ones).

The product of its (nonzero) digits is 13608, while the sum is 36.

The spelling of 66011391720 in words is "sixty-six billion, eleven million, three hundred ninety-one thousand, seven hundred twenty".