1661307804 has 144 divisors (see below), whose sum is σ = 4725520800. Its totient is φ = 488581632.

The previous prime is 1661307803. The next prime is 1661307811. The reversal of 1661307804 is 4087031661.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661307803) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1478787 + ... + 1479909.

Almost surely, 2^1661307804 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1661307804, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2362760400).

1661307804 is an abundant number, since it is smaller than the sum of its proper divisors (3064212996).

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

1661307804 is a wasteful number, since it uses less digits than its factorization.

1661307804 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1284 (or 1279 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

The square root of 1661307804 is about 40759.1438084757. The cubic root of 1661307804 is about 1184.3590102793.

The spelling of 1661307804 in words is "one billion, six hundred sixty-one million, three hundred seven thousand, eight hundred four".