15961969 has 4 divisors (see below), whose sum is σ = 15975540. Its totient is φ = 15948400.

The previous prime is 15961951. The next prime is 15961973. The reversal of 15961969 is 96916951.

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

It can be written as a sum of positive squares in 2 ways, for example, as 6426225 + 9535744 = 2535^2 + 3088^2 .

It is a cyclic number.

It is not a de Polignac number, because 15961969 - 2⁹ = 15961457 is a prime.

It is a super-2 number, since 2×15961969² = 509568908713922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15961909) 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, 4834 + ... + 7435.

It is an arithmetic number, because the mean of its divisors is an integer number (3993885).

Almost surely, 2^15961969 is an apocalyptic number.

It is an amenable number.

15961969 is a deficient number, since it is larger than the sum of its proper divisors (13571).

15961969 is a wasteful number, since it uses less digits than its factorization.

15961969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13570.

The product of its digits is 131220, while the sum is 46.

The square root of 15961969 is about 3995.2432967217. The cubic root of 15961969 is about 251.7844013450.

It can be divided in two parts, 159 and 61969, that added together give a triangular number (62128 = T₃₅₂).

The spelling of 15961969 in words is "fifteen million, nine hundred sixty-one thousand, nine hundred sixty-nine".