20961965 has 8 divisors (see below), whose sum is σ = 25347168. Its totient is φ = 16641040.

The previous prime is 20961961. The next prime is 20962013. The reversal of 20961965 is 56916902.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20961965 - 2² = 20961961 is a prime.

It is a super-2 number, since 2×20961965² = 878807953322450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20961961) 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 7 ways as a sum of consecutive naturals, for example, 15347 + ... + 16656.

It is an arithmetic number, because the mean of its divisors is an integer number (3168396).

Almost surely, 2^20961965 is an apocalyptic number.

It is an amenable number.

20961965 is a deficient number, since it is larger than the sum of its proper divisors (4385203).

20961965 is a wasteful number, since it uses less digits than its factorization.

20961965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32139.

The product of its (nonzero) digits is 29160, while the sum is 38.

The square root of 20961965 is about 4578.4238554332. The cubic root of 20961965 is about 275.7257524037.

The spelling of 20961965 in words is "twenty million, nine hundred sixty-one thousand, nine hundred sixty-five".