1881631 has 2 divisors, whose sum is σ = 1881632. Its totient is φ = 1881630.

The previous prime is 1881619. The next prime is 1881641. The reversal of 1881631 is 1361881.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1881631 - 2⁹ = 1881119 is a prime.

It is a super-2 number, since 2×1881631² = 7081070440322, which contains 22 as substring.

1881631 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 1881631.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1881601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 940815 + 940816.

It is an arithmetic number, because the mean of its divisors is an integer number (940816).

2^1881631 is an apocalyptic number.

1881631 is a deficient number, since it is larger than the sum of its proper divisors (1).

1881631 is an equidigital number, since it uses as much as digits as its factorization.

1881631 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1152, while the sum is 28.

The square root of 1881631 is about 1371.7255556415. The cubic root of 1881631 is about 123.4557967110.

The spelling of 1881631 in words is "one million, eight hundred eighty-one thousand, six hundred thirty-one".