1215000091 has 2 divisors, whose sum is σ = 1215000092. Its totient is φ = 1215000090.

The previous prime is 1215000079. The next prime is 1215000097. The reversal of 1215000091 is 1900005121.

1215000091 = T₂₈₄₅₉ + T₂₈₄₆₀ + T₂₈₄₆₁.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1215000091 - 2⁹ = 1214999579 is a prime.

It is a super-2 number, since 2×1215000091² = 2952450442260016562, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1215000097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 607500045 + 607500046.

It is an arithmetic number, because the mean of its divisors is an integer number (607500046).

Almost surely, 2^1215000091 is an apocalyptic number.

1215000091 is the 28461-st centered triangular number.

1215000091 is a deficient number, since it is larger than the sum of its proper divisors (1).

1215000091 is an equidigital number, since it uses as much as digits as its factorization.

1215000091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 90, while the sum is 19.

The square root of 1215000091 is about 34856.8514212056. The cubic root of 1215000091 is about 1067.0680179871.

The spelling of 1215000091 in words is "one billion, two hundred fifteen million, ninety-one", and thus it is an aban number.