1661472377 has 4 divisors (see below), whose sum is σ = 1661555700. Its totient is φ = 1661389056.

The previous prime is 1661472317. The next prime is 1661472401. The reversal of 1661472377 is 7732741661.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 355661881 + 1305810496 = 18859^2 + 36136^2 .

It is a cyclic number.

It is not a de Polignac number, because 1661472377 - 2²⁴ = 1644695161 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661472317) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7913 + ... + 58185.

It is an arithmetic number, because the mean of its divisors is an integer number (415388925).

Almost surely, 2^1661472377 is an apocalyptic number.

It is an amenable number.

1661472377 is a deficient number, since it is larger than the sum of its proper divisors (83323).

1661472377 is an equidigital number, since it uses as much as digits as its factorization.

1661472377 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83322.

The product of its digits is 296352, while the sum is 44.

The square root of 1661472377 is about 40761.1626060887. The cubic root of 1661472377 is about 1184.3981174371.

The spelling of 1661472377 in words is "one billion, six hundred sixty-one million, four hundred seventy-two thousand, three hundred seventy-seven".