1215919 has 2 divisors, whose sum is σ = 1215920. Its totient is φ = 1215918.

The previous prime is 1215917. The next prime is 1215923. The reversal of 1215919 is 9195121.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1215919 - 2¹ = 1215917 is a prime.

It is a super-2 number, since 2×1215919² = 2956918029122, which contains 22 as substring.

Together with 1215917, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1215917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 607959 + 607960.

It is an arithmetic number, because the mean of its divisors is an integer number (607960).

2^1215919 is an apocalyptic number.

1215919 is a deficient number, since it is larger than the sum of its proper divisors (1).

1215919 is an equidigital number, since it uses as much as digits as its factorization.

1215919 is an evil number, because the sum of its binary digits is even.

The product of its digits is 810, while the sum is 28.

The square root of 1215919 is about 1102.6871723204. The cubic root of 1215919 is about 106.7336959343.

It can be divided in two parts, 12 and 15919, that added together give a triangular number (15931 = T₁₇₈).

The spelling of 1215919 in words is "one million, two hundred fifteen thousand, nine hundred nineteen".