840021023 has 2 divisors, whose sum is σ = 840021024. Its totient is φ = 840021022.

The previous prime is 840021011. The next prime is 840021029. The reversal of 840021023 is 320120048.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 840021023 - 2²⁶ = 772912159 is a prime.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 840020986 and 840021004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (840021029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 420010511 + 420010512.

It is an arithmetic number, because the mean of its divisors is an integer number (420010512).

Almost surely, 2^840021023 is an apocalyptic number.

840021023 is a deficient number, since it is larger than the sum of its proper divisors (1).

840021023 is an equidigital number, since it uses as much as digits as its factorization.

840021023 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 840021023 is about 28983.1161713160. The cubic root of 840021023 is about 943.5466674326.

The spelling of 840021023 in words is "eight hundred forty million, twenty-one thousand, twenty-three".