215542161 has 8 divisors (see below), whose sum is σ = 319321760. Its totient is φ = 143694756.

The previous prime is 215542147. The next prime is 215542169. The reversal of 215542161 is 161245512.

215542161 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 215542161 - 2²³ = 207153553 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 7983043 = 215542161 / (2 + 1 + 5 + 5 + 4 + 2 + 1 + 6 + 1).

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (215542169) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3991495 + ... + 3991548.

It is an arithmetic number, because the mean of its divisors is an integer number (39915220).

Almost surely, 2^215542161 is an apocalyptic number.

It is an amenable number.

215542161 is a deficient number, since it is larger than the sum of its proper divisors (103779599).

215542161 is an equidigital number, since it uses as much as digits as its factorization.

215542161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7983052 (or 7983046 counting only the distinct ones).

The product of its digits is 2400, while the sum is 27.

The square root of 215542161 is about 14681.3541950326. The cubic root of 215542161 is about 599.5757751261.

Adding to 215542161 its reverse (161245512), we get a palindrome (376787673).

The spelling of 215542161 in words is "two hundred fifteen million, five hundred forty-two thousand, one hundred sixty-one".