65961815 has 16 divisors (see below), whose sum is σ = 82814400. Its totient is φ = 50341632.

The previous prime is 65961809. The next prime is 65961817. The reversal of 65961815 is 51816956.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-65961815 is a prime.

It is a super-2 number, since 2×65961815² = 8701922076188450, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65961817) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 81131 + ... + 81939.

It is an arithmetic number, because the mean of its divisors is an integer number (5175900).

Almost surely, 2^65961815 is an apocalyptic number.

65961815 is a deficient number, since it is larger than the sum of its proper divisors (16852585).

65961815 is a wasteful number, since it uses less digits than its factorization.

65961815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1546.

The product of its digits is 64800, while the sum is 41.

The square root of 65961815 is about 8121.6879403237. The cubic root of 65961815 is about 404.0460502845.

The spelling of 65961815 in words is "sixty-five million, nine hundred sixty-one thousand, eight hundred fifteen".