15961663 has 4 divisors (see below), whose sum is σ = 15973848. Its totient is φ = 15949480.

The previous prime is 15961651. The next prime is 15961697. The reversal of 15961663 is 36616951.

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 15961663 - 2¹³ = 15953471 is a prime.

It is a Duffinian number.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15968663) 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, 3853 + ... + 6838.

It is an arithmetic number, because the mean of its divisors is an integer number (3993462).

Almost surely, 2^15961663 is an apocalyptic number.

15961663 is a deficient number, since it is larger than the sum of its proper divisors (12185).

15961663 is a wasteful number, since it uses less digits than its factorization.

15961663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12184.

The product of its digits is 29160, while the sum is 37.

The square root of 15961663 is about 3995.2050009981. The cubic root of 15961663 is about 251.7827923848.

The spelling of 15961663 in words is "fifteen million, nine hundred sixty-one thousand, six hundred sixty-three".