1661323087 has 4 divisors (see below), whose sum is σ = 1718610120. Its totient is φ = 1604036056.

The previous prime is 1661323021. The next prime is 1661323109. The reversal of 1661323087 is 7803231661.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1661323087 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661323987) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28643473 + ... + 28643530.

It is an arithmetic number, because the mean of its divisors is an integer number (429652530).

Almost surely, 2^1661323087 is an apocalyptic number.

1661323087 is a deficient number, since it is larger than the sum of its proper divisors (57287033).

1661323087 is an equidigital number, since it uses as much as digits as its factorization.

1661323087 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57287032.

The product of its (nonzero) digits is 36288, while the sum is 37.

The square root of 1661323087 is about 40759.3312874488. The cubic root of 1661323087 is about 1184.3626420572.

The spelling of 1661323087 in words is "one billion, six hundred sixty-one million, three hundred twenty-three thousand, eighty-seven".