1987780867 has 2 divisors, whose sum is σ = 1987780868. Its totient is φ = 1987780866.

The previous prime is 1987780763. The next prime is 1987780877. The reversal of 1987780867 is 7680877891.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1987780867 is a prime.

It is a super-2 number, since 2×1987780867² = 7902545550422543378, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1987780877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 993890433 + 993890434.

It is an arithmetic number, because the mean of its divisors is an integer number (993890434).

Almost surely, 2^1987780867 is an apocalyptic number.

1987780867 is a deficient number, since it is larger than the sum of its proper divisors (1).

1987780867 is an equidigital number, since it uses as much as digits as its factorization.

1987780867 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9483264, while the sum is 61.

The square root of 1987780867 is about 44584.5361868888. The cubic root of 1987780867 is about 1257.3499495148.

The spelling of 1987780867 in words is "one billion, nine hundred eighty-seven million, seven hundred eighty thousand, eight hundred sixty-seven".