64961591 has 4 divisors (see below), whose sum is σ = 67786032. Its totient is φ = 62137152.

The previous prime is 64961549. The next prime is 64961593. The reversal of 64961591 is 19516946.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19516946 = 2 ⋅9758473.

It is a cyclic number.

It is not a de Polignac number, because 64961591 - 2¹⁴ = 64945207 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64961593) 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, 1412186 + ... + 1412231.

It is an arithmetic number, because the mean of its divisors is an integer number (16946508).

Almost surely, 2^64961591 is an apocalyptic number.

64961591 is a deficient number, since it is larger than the sum of its proper divisors (2824441).

64961591 is a wasteful number, since it uses less digits than its factorization.

64961591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2824440.

The product of its digits is 58320, while the sum is 41.

The square root of 64961591 is about 8059.8753712449. The cubic root of 64961591 is about 401.9933643286.

The spelling of 64961591 in words is "sixty-four million, nine hundred sixty-one thousand, five hundred ninety-one".