65440251 has 16 divisors (see below), whose sum is σ = 98540320. Its totient is φ = 42910560.

The previous prime is 65440247. The next prime is 65440253. The reversal of 65440251 is 15204456.

65440251 is a `hidden beast` number, since 654 + 4 + 0 + 2 + 5 + 1 = 666.

It is not a de Polignac number, because 65440251 - 2² = 65440247 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (65440253) 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 15 ways as a sum of consecutive naturals, for example, 18220 + ... + 21513.

It is an arithmetic number, because the mean of its divisors is an integer number (6158770).

Almost surely, 2^65440251 is an apocalyptic number.

65440251 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

65440251 is a deficient number, since it is larger than the sum of its proper divisors (33100069).

65440251 is a wasteful number, since it uses less digits than its factorization.

65440251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39803 (or 39797 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

The square root of 65440251 is about 8089.5148803868. The cubic root of 65440251 is about 402.9782923161.

The spelling of 65440251 in words is "sixty-five million, four hundred forty thousand, two hundred fifty-one".