66826861 has 4 divisors (see below), whose sum is σ = 66844800. Its totient is φ = 66808924.

The previous prime is 66826849. The next prime is 66826871. The reversal of 66826861 is 16862866.

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 66826861 - 2⁷ = 66826733 is a prime.

It is a super-2 number, since 2×66826861² = 8931658702226642, 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 (66826841) 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, 1051 + ... + 11608.

It is an arithmetic number, because the mean of its divisors is an integer number (16711200).

Almost surely, 2^66826861 is an apocalyptic number.

It is an amenable number.

66826861 is a deficient number, since it is larger than the sum of its proper divisors (17939).

66826861 is a wasteful number, since it uses less digits than its factorization.

66826861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17938.

The product of its digits is 165888, while the sum is 43.

The square root of 66826861 is about 8174.7697826911. The cubic root of 66826861 is about 405.8046513448.

The spelling of 66826861 in words is "sixty-six million, eight hundred twenty-six thousand, eight hundred sixty-one".