66651956 has 18 divisors (see below), whose sum is σ = 135684738. Its totient is φ = 28565040.

The previous prime is 66651941. The next prime is 66651961. The reversal of 66651956 is 65915666.

It can be written as a sum of positive squares in only one way, i.e., 66161956 + 490000 = 8134^2 + 700^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 169835 + ... + 170226.

It is an arithmetic number, because the mean of its divisors is an integer number (7538041).

Almost surely, 2^66651956 is an apocalyptic number.

It is an amenable number.

66651956 is an abundant number, since it is smaller than the sum of its proper divisors (69032782).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66651956 is a wasteful number, since it uses less digits than its factorization.

66651956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 340079 (or 340070 counting only the distinct ones).

The product of its digits is 291600, while the sum is 44.

The square root of 66651956 is about 8164.0649188992. The cubic root of 66651956 is about 405.4503064289.

The spelling of 66651956 in words is "sixty-six million, six hundred fifty-one thousand, nine hundred fifty-six".