1215987 has 8 divisors (see below), whose sum is σ = 1691904. Its totient is φ = 775368.

The previous prime is 1215923. The next prime is 1216009. The reversal of 1215987 is 7895121.

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

It is not a de Polignac number, because 1215987 - 2⁶ = 1215923 is a prime.

It is a d-powerful number, because it can be written as 1 + 2¹⁰ + 1 + 5⁸ + 9³ + 8² + 7⁷ .

1215987 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1215917) 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, 8743 + ... + 8880.

It is an arithmetic number, because the mean of its divisors is an integer number (211488).

2^1215987 is an apocalyptic number.

1215987 is a deficient number, since it is larger than the sum of its proper divisors (475917).

1215987 is a wasteful number, since it uses less digits than its factorization.

1215987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17649.

The product of its digits is 5040, while the sum is 33.

The square root of 1215987 is about 1102.7180056569. The cubic root of 1215987 is about 106.7356855833.

Adding to 1215987 its sum of digits (33), we get a triangular number (1216020 = T₁₅₅₉).

It can be divided in two parts, 12159 and 87, that added together give a triangular number (12246 = T₁₅₆).

The spelling of 1215987 in words is "one million, two hundred fifteen thousand, nine hundred eighty-seven".