65021561 has 4 divisors (see below), whose sum is σ = 70932624. Its totient is φ = 59110500.

The previous prime is 65021521. The next prime is 65021563. The reversal of 65021561 is 16512056.

65021561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 65021561 - 2⁶ = 65021497 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 65021561.

It is not an unprimeable number, because it can be changed into a prime (65021563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2955515 + ... + 2955536.

It is an arithmetic number, because the mean of its divisors is an integer number (17733156).

Almost surely, 2^65021561 is an apocalyptic number.

It is an amenable number.

65021561 is a deficient number, since it is larger than the sum of its proper divisors (5911063).

65021561 is a wasteful number, since it uses less digits than its factorization.

65021561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5911062.

The product of its (nonzero) digits is 1800, while the sum is 26.

The square root of 65021561 is about 8063.5947938869. The cubic root of 65021561 is about 402.1170277997.

The spelling of 65021561 in words is "sixty-five million, twenty-one thousand, five hundred sixty-one".