1661121792 has 108 divisors (see below), whose sum is σ = 5224905504. Its totient is φ = 503362560.

The previous prime is 1661121757. The next prime is 1661121811. The reversal of 1661121792 is 2971211661.

1661121792 is a `hidden beast` number, since 16 + 611 + 21 + 7 + 9 + 2 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7428 + ... + 58115.

Almost surely, 2^1661121792 is an apocalyptic number.

1661121792 is a gapful number since it is divisible by the number (12) 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 1661121792, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2612452752).

1661121792 is an abundant number, since it is smaller than the sum of its proper divisors (3563783712).

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

1661121792 is a wasteful number, since it uses less digits than its factorization.

1661121792 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65576 (or 65559 counting only the distinct ones).

The product of its digits is 9072, while the sum is 36.

The square root of 1661121792 is about 40756.8619007892. The cubic root of 1661121792 is about 1184.3148055047.

The spelling of 1661121792 in words is "one billion, six hundred sixty-one million, one hundred twenty-one thousand, seven hundred ninety-two".