1661923895 has 4 divisors (see below), whose sum is σ = 1994308680. Its totient is φ = 1329539112.

The previous prime is 1661923873. The next prime is 1661923897. The reversal of 1661923895 is 5983291661.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1661923895 - 2⁶ = 1661923831 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661923897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 166192385 + ... + 166192394.

It is an arithmetic number, because the mean of its divisors is an integer number (498577170).

Almost surely, 2^1661923895 is an apocalyptic number.

1661923895 is a deficient number, since it is larger than the sum of its proper divisors (332384785).

1661923895 is an equidigital number, since it uses as much as digits as its factorization.

1661923895 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 332384784.

The product of its digits is 699840, while the sum is 50.

The square root of 1661923895 is about 40766.7008108333. The cubic root of 1661923895 is about 1184.5053975100.

The spelling of 1661923895 in words is "one billion, six hundred sixty-one million, nine hundred twenty-three thousand, eight hundred ninety-five".