1661736959 has 4 divisors (see below), whose sum is σ = 1733986416. Its totient is φ = 1589487504.

The previous prime is 1661736919. The next prime is 1661736971. The reversal of 1661736959 is 9596371661.

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-1661736959 is a prime.

It is a super-2 number, since 2×1661736959² = 5522739441813135362, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1661736959.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661736919) 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, 36124694 + ... + 36124739.

It is an arithmetic number, because the mean of its divisors is an integer number (433496604).

Almost surely, 2^1661736959 is an apocalyptic number.

1661736959 is a deficient number, since it is larger than the sum of its proper divisors (72249457).

1661736959 is an equidigital number, since it uses as much as digits as its factorization.

1661736959 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72249456.

The product of its digits is 1837080, while the sum is 53.

The square root of 1661736959 is about 40764.4079927576. The cubic root of 1661736959 is about 1184.4609841238.

The spelling of 1661736959 in words is "one billion, six hundred sixty-one million, seven hundred thirty-six thousand, nine hundred fifty-nine".