66126661 has 4 divisors (see below), whose sum is σ = 66161772. Its totient is φ = 66091552.

The previous prime is 66126637. The next prime is 66126667. The reversal of 66126661 is 16662166.

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

It can be written as a sum of positive squares in 2 ways, for example, as 7128900 + 58997761 = 2670^2 + 7681^2 .

It is a cyclic number.

It is not a de Polignac number, because 66126661 - 2¹¹ = 66124613 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66126667) 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, 14560 + ... + 18553.

It is an arithmetic number, because the mean of its divisors is an integer number (16540443).

Almost surely, 2^66126661 is an apocalyptic number.

It is an amenable number.

66126661 is a deficient number, since it is larger than the sum of its proper divisors (35111).

66126661 is a wasteful number, since it uses less digits than its factorization.

66126661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35110.

The product of its digits is 15552, while the sum is 34.

The square root of 66126661 is about 8131.8301138182. The cubic root of 66126661 is about 404.3823558038.

The spelling of 66126661 in words is "sixty-six million, one hundred twenty-six thousand, six hundred sixty-one".