2155772729 has 4 divisors (see below), whose sum is σ = 2351752080. Its totient is φ = 1959793380.

The previous prime is 2155772719. The next prime is 2155772741. The reversal of 2155772729 is 9272775512.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 2155772729 - 2⁴ = 2155772713 is a prime.

It is a super-3 number, since 3×2155772729³ (a number of 29 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2155772719) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 97989659 + ... + 97989680.

It is an arithmetic number, because the mean of its divisors is an integer number (587938020).

Almost surely, 2^2155772729 is an apocalyptic number.

It is an amenable number.

2155772729 is a deficient number, since it is larger than the sum of its proper divisors (195979351).

2155772729 is a wasteful number, since it uses less digits than its factorization.

2155772729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195979350.

The product of its digits is 617400, while the sum is 47.

The square root of 2155772729 is about 46430.2996867347. The cubic root of 2155772729 is about 1291.8169874438.

The spelling of 2155772729 in words is "two billion, one hundred fifty-five million, seven hundred seventy-two thousand, seven hundred twenty-nine".