1961987143 has 2 divisors, whose sum is σ = 1961987144. Its totient is φ = 1961987142.

The previous prime is 1961987077. The next prime is 1961987149. The reversal of 1961987143 is 3417891691.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1961987143 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1961987149) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 980993571 + 980993572.

It is an arithmetic number, because the mean of its divisors is an integer number (980993572).

Almost surely, 2^1961987143 is an apocalyptic number.

1961987143 is a deficient number, since it is larger than the sum of its proper divisors (1).

1961987143 is an equidigital number, since it uses as much as digits as its factorization.

1961987143 is an evil number, because the sum of its binary digits is even.

The product of its digits is 326592, while the sum is 49.

The square root of 1961987143 is about 44294.3240494761. The cubic root of 1961987143 is about 1251.8877382271.

The spelling of 1961987143 in words is "one billion, nine hundred sixty-one million, nine hundred eighty-seven thousand, one hundred forty-three".