1987019761 has 2 divisors, whose sum is σ = 1987019762. Its totient is φ = 1987019760.

The previous prime is 1987019729. The next prime is 1987019807. The reversal of 1987019761 is 1679107891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1579585536 + 407434225 = 39744^2 + 20185^2 .

It is a cyclic number.

It is not a de Polignac number, because 1987019761 - 2⁵ = 1987019729 is a prime.

It is not a weakly prime, because it can be changed into another prime (1987019701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 993509880 + 993509881.

It is an arithmetic number, because the mean of its divisors is an integer number (993509881).

Almost surely, 2^1987019761 is an apocalyptic number.

It is an amenable number.

1987019761 is a deficient number, since it is larger than the sum of its proper divisors (1).

1987019761 is an equidigital number, since it uses as much as digits as its factorization.

1987019761 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 190512, while the sum is 49.

The square root of 1987019761 is about 44575.9998317480. Note that the first 3 decimals coincide. The cubic root of 1987019761 is about 1257.1894524882.

The spelling of 1987019761 in words is "one billion, nine hundred eighty-seven million, nineteen thousand, seven hundred sixty-one".