2155661615 has 16 divisors (see below), whose sum is σ = 2632524960. Its totient is φ = 1694113920.

The previous prime is 2155661581. The next prime is 2155661617. The reversal of 2155661615 is 5161665512.

It is a happy number.

It is not a de Polignac number, because 2155661615 - 2¹⁸ = 2155399471 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2155661617) 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, 263456 + ... + 271514.

It is an arithmetic number, because the mean of its divisors is an integer number (164532810).

Almost surely, 2^2155661615 is an apocalyptic number.

2155661615 is a deficient number, since it is larger than the sum of its proper divisors (476863345).

2155661615 is an equidigital number, since it uses as much as digits as its factorization.

2155661615 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9002.

The product of its digits is 54000, while the sum is 38.

The square root of 2155661615 is about 46429.1031035492. The cubic root of 2155661615 is about 1291.7947925533.

The spelling of 2155661615 in words is "two billion, one hundred fifty-five million, six hundred sixty-one thousand, six hundred fifteen".