1561222087 has 2 divisors, whose sum is σ = 1561222088. Its totient is φ = 1561222086.

The previous prime is 1561222043. The next prime is 1561222097. The reversal of 1561222087 is 7802221651.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1561222087 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1561222097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 780611043 + 780611044.

It is an arithmetic number, because the mean of its divisors is an integer number (780611044).

Almost surely, 2^1561222087 is an apocalyptic number.

1561222087 is a deficient number, since it is larger than the sum of its proper divisors (1).

1561222087 is an equidigital number, since it uses as much as digits as its factorization.

1561222087 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13440, while the sum is 34.

The square root of 1561222087 is about 39512.3029827420. The cubic root of 1561222087 is about 1160.0807729625.

The spelling of 1561222087 in words is "one billion, five hundred sixty-one million, two hundred twenty-two thousand, eighty-seven".