1215012161 has 4 divisors (see below), whose sum is σ = 1325467824. Its totient is φ = 1104556500.

The previous prime is 1215012143. The next prime is 1215012221. The reversal of 1215012161 is 1612105121.

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 1215012161 - 2¹⁴ = 1214995777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1215012131) 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, 55227815 + ... + 55227836.

It is an arithmetic number, because the mean of its divisors is an integer number (331366956).

Almost surely, 2^1215012161 is an apocalyptic number.

1215012161 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1215012161 is a deficient number, since it is larger than the sum of its proper divisors (110455663).

1215012161 is a wasteful number, since it uses less digits than its factorization.

1215012161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110455662.

The product of its (nonzero) digits is 120, while the sum is 20.

The square root of 1215012161 is about 34857.0245574690. The cubic root of 1215012161 is about 1067.0715514487.

Adding to 1215012161 its reverse (1612105121), we get a palindrome (2827117282).

The spelling of 1215012161 in words is "one billion, two hundred fifteen million, twelve thousand, one hundred sixty-one".