65405551 has 4 divisors (see below), whose sum is σ = 66639672. Its totient is φ = 64171432.

The previous prime is 65405539. The next prime is 65405563. The reversal of 65405551 is 15550456.

65405551 is nontrivially palindromic in base 4.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (65405539) and next prime (65405563).

It is a cyclic number.

It is not a de Polignac number, because 65405551 - 2⁵ = 65405519 is a prime.

It is a super-2 number, since 2×65405551² = 8555772203227202, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65405521) 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, 616981 + ... + 617086.

It is an arithmetic number, because the mean of its divisors is an integer number (16659918).

Almost surely, 2^65405551 is an apocalyptic number.

65405551 is a deficient number, since it is larger than the sum of its proper divisors (1234121).

65405551 is a wasteful number, since it uses less digits than its factorization.

65405551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1234120.

The product of its (nonzero) digits is 15000, while the sum is 31.

The square root of 65405551 is about 8087.3698443932. The cubic root of 65405551 is about 402.9070526798.

It can be divided in two parts, 65405 and 551, that added together give a palindrome (65956).

The spelling of 65405551 in words is "sixty-five million, four hundred five thousand, five hundred fifty-one".