1661321272 has 16 divisors (see below), whose sum is σ = 3354591240. Its totient is φ = 766763616.

The previous prime is 1661321251. The next prime is 1661321273. The reversal of 1661321272 is 2721231661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661321273) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7987018 + ... + 7987225.

Almost surely, 2^1661321272 is an apocalyptic number.

It is an amenable number.

1661321272 is an abundant number, since it is smaller than the sum of its proper divisors (1693269968).

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

1661321272 is a wasteful number, since it uses less digits than its factorization.

1661321272 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15974262 (or 15974258 counting only the distinct ones).

The product of its digits is 6048, while the sum is 31.

The square root of 1661321272 is about 40759.3090226024. The cubic root of 1661321272 is about 1184.3622107506.

The spelling of 1661321272 in words is "one billion, six hundred sixty-one million, three hundred twenty-one thousand, two hundred seventy-two".