840898381 has 2 divisors, whose sum is σ = 840898382. Its totient is φ = 840898380.

The previous prime is 840898379. The next prime is 840898403. The reversal of 840898381 is 183898048.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 840710025 + 188356 = 28995^2 + 434^2 .

It is a cyclic number.

It is not a de Polignac number, because 840898381 - 2¹ = 840898379 is a prime.

It is a super-2 number, since 2×840898381² = 1414220174336842322, which contains 22 as substring.

Together with 840898379, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (840898321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 420449190 + 420449191.

It is an arithmetic number, because the mean of its divisors is an integer number (420449191).

Almost surely, 2^840898381 is an apocalyptic number.

It is an amenable number.

840898381 is a deficient number, since it is larger than the sum of its proper divisors (1).

840898381 is an equidigital number, since it uses as much as digits as its factorization.

840898381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 442368, while the sum is 49.

The square root of 840898381 is about 28998.2478953471. The cubic root of 840898381 is about 943.8750481730.

The spelling of 840898381 in words is "eight hundred forty million, eight hundred ninety-eight thousand, three hundred eighty-one".