1972781 has 2 divisors, whose sum is σ = 1972782. Its totient is φ = 1972780.

The previous prime is 1972777. The next prime is 1972787. The reversal of 1972781 is 1872791.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1755625 + 217156 = 1325^2 + 466^2 .

It is a cyclic number.

It is not a de Polignac number, because 1972781 - 2² = 1972777 is a prime.

It is a super-3 number, since 3×1972781³ = 23033391233752966623, which contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1972787) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 986390 + 986391.

It is an arithmetic number, because the mean of its divisors is an integer number (986391).

2^1972781 is an apocalyptic number.

It is an amenable number.

1972781 is a deficient number, since it is larger than the sum of its proper divisors (1).

1972781 is an equidigital number, since it uses as much as digits as its factorization.

1972781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7056, while the sum is 35.

The square root of 1972781 is about 1404.5572256053. The cubic root of 1972781 is about 125.4179291247.

The spelling of 1972781 in words is "one million, nine hundred seventy-two thousand, seven hundred eighty-one".