1866540657 has 16 divisors (see below), whose sum is σ = 2545201152. Its totient is φ = 1216194000.

The previous prime is 1866540629. The next prime is 1866540661. The reversal of 1866540657 is 7560456681.

It is not a de Polignac number, because 1866540657 - 2⁶ = 1866540593 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1866540257) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 97078 + ... + 114704.

It is an arithmetic number, because the mean of its divisors is an integer number (159075072).

Almost surely, 2^1866540657 is an apocalyptic number.

It is an amenable number.

1866540657 is a deficient number, since it is larger than the sum of its proper divisors (678660495).

1866540657 is a wasteful number, since it uses less digits than its factorization.

1866540657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18428.

The product of its (nonzero) digits is 1209600, while the sum is 48.

The square root of 1866540657 is about 43203.4796862475. The cubic root of 1866540657 is about 1231.2487938284.

The spelling of 1866540657 in words is "one billion, eight hundred sixty-six million, five hundred forty thousand, six hundred fifty-seven".