1215111001 has 8 divisors (see below), whose sum is σ = 1311882824. Its totient is φ = 1118810880.

The previous prime is 1215110983. The next prime is 1215111011. The reversal of 1215111001 is 1001115121.

It can be written as a sum of positive squares in 4 ways, for example, as 310605376 + 904505625 = 17624^2 + 30075^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1215111001 - 2⁷ = 1215110873 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1215111011) 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, 112560 + ... + 122881.

It is an arithmetic number, because the mean of its divisors is an integer number (163985353).

Almost surely, 2^1215111001 is an apocalyptic number.

It is an amenable number.

1215111001 is a deficient number, since it is larger than the sum of its proper divisors (96771823).

1215111001 is a wasteful number, since it uses less digits than its factorization.

1215111001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 235851.

The product of its (nonzero) digits is 10, while the sum is 13.

The square root of 1215111001 is about 34858.4423203332. The cubic root of 1215111001 is about 1067.1004857249.

Adding to 1215111001 its reverse (1001115121), we get a palindrome (2216226122).

The spelling of 1215111001 in words is "one billion, two hundred fifteen million, one hundred eleven thousand, one".