66261554 has 8 divisors (see below), whose sum is σ = 101267820. Its totient is φ = 32505616.

The previous prime is 66261553. The next prime is 66261571. The reversal of 66261554 is 45516266.

66261554 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 64080025 + 2181529 = 8005^2 + 1477^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (66261553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 312449 + ... + 312660.

Almost surely, 2^66261554 is an apocalyptic number.

66261554 is a deficient number, since it is larger than the sum of its proper divisors (35006266).

66261554 is a wasteful number, since it uses less digits than its factorization.

66261554 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 625164.

The product of its digits is 43200, while the sum is 35.

The square root of 66261554 is about 8140.1200236852. The cubic root of 66261554 is about 404.6571380619.

The spelling of 66261554 in words is "sixty-six million, two hundred sixty-one thousand, five hundred fifty-four".