120666781 has 4 divisors (see below), whose sum is σ = 121407232. Its totient is φ = 119926332.

The previous prime is 120666769. The next prime is 120666797. The reversal of 120666781 is 187666021.

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, and also an emirpimes, since its reverse is a distinct semiprime: 187666021 = 19 ⋅9877159.

It is a cyclic number.

It is not a de Polignac number, because 120666781 - 2¹⁹ = 120142493 is a prime.

It is a super-2 number, since 2×120666781² = 29120944073803922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 120666781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (120666181) 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, 369981 + ... + 370306.

It is an arithmetic number, because the mean of its divisors is an integer number (30351808).

Almost surely, 2^120666781 is an apocalyptic number.

It is an amenable number.

120666781 is a deficient number, since it is larger than the sum of its proper divisors (740451).

120666781 is an equidigital number, since it uses as much as digits as its factorization.

120666781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 740450.

The product of its (nonzero) digits is 24192, while the sum is 37.

The square root of 120666781 is about 10984.8432396644. The cubic root of 120666781 is about 494.1542965160.

The spelling of 120666781 in words is "one hundred twenty million, six hundred sixty-six thousand, seven hundred eighty-one".