66261311 has 4 divisors (see below), whose sum is σ = 67347624. Its totient is φ = 65175000.

The previous prime is 66261287. The next prime is 66261313. The reversal of 66261311 is 11316266.

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 66261311 - 2¹⁰ = 66260287 is a prime.

It is a super-2 number, since 2×66261311² = 8781122670877442, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66261313) 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, 543065 + ... + 543186.

It is an arithmetic number, because the mean of its divisors is an integer number (16836906).

Almost surely, 2^66261311 is an apocalyptic number.

66261311 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

66261311 is a deficient number, since it is larger than the sum of its proper divisors (1086313).

66261311 is a wasteful number, since it uses less digits than its factorization.

66261311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1086312.

The product of its digits is 1296, while the sum is 26.

The square root of 66261311 is about 8140.1050976016. The cubic root of 66261311 is about 404.6566433970.

Adding to 66261311 its reverse (11316266), we get a palindrome (77577577).

The spelling of 66261311 in words is "sixty-six million, two hundred sixty-one thousand, three hundred eleven".