65621251 has 4 divisors (see below), whose sum is σ = 65804400. Its totient is φ = 65438104.

The previous prime is 65621249. The next prime is 65621263. The reversal of 65621251 is 15212656.

65621251 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.

It is a cyclic number.

It is not a de Polignac number, because 65621251 - 2¹ = 65621249 is a prime.

It is a super-2 number, since 2×65621251² = 8612297165610002, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (65621551) 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, 91036 + ... + 91753.

It is an arithmetic number, because the mean of its divisors is an integer number (16451100).

Almost surely, 2^65621251 is an apocalyptic number.

65621251 is a deficient number, since it is larger than the sum of its proper divisors (183149).

65621251 is a wasteful number, since it uses less digits than its factorization.

65621251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 183148.

The product of its digits is 3600, while the sum is 28.

The square root of 65621251 is about 8100.6944764014. The cubic root of 65621251 is about 403.3494804151.

The spelling of 65621251 in words is "sixty-five million, six hundred twenty-one thousand, two hundred fifty-one".