1660390380 has 384 divisors, whose sum is σ = 5945425920. Its totient is φ = 381024000.

The previous prime is 1660390367. The next prime is 1660390397. The reversal of 1660390380 is 830930661.

It is a happy number.

1660390380 is a `hidden beast` number, since 16 + 603 + 9 + 0 + 38 + 0 = 666.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 13073877 + ... + 13074003.

It is an arithmetic number, because the mean of its divisors is an integer number (15482880).

Almost surely, 2^1660390380 is an apocalyptic number.

1660390380 is a gapful number since it is divisible by the number (10) 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 1660390380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2972712960).

1660390380 is an abundant number, since it is smaller than the sum of its proper divisors (4285035540).

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

1660390380 is a wasteful number, since it uses less digits than its factorization.

1660390380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 258 (or 250 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 36.

The square root of 1660390380 is about 40747.8880434312. Note that the first 3 decimals coincide. The cubic root of 1660390380 is about 1184.1409572792.

The spelling of 1660390380 in words is "one billion, six hundred sixty million, three hundred ninety thousand, three hundred eighty".