40238021 has 2 divisors, whose sum is σ = 40238022. Its totient is φ = 40238020.

The previous prime is 40237961. The next prime is 40238039. The reversal of 40238021 is 12083204.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 37957921 + 2280100 = 6161^2 + 1510^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-40238021 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 40237984 and 40238002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (40238041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20119010 + 20119011.

It is an arithmetic number, because the mean of its divisors is an integer number (20119011).

Almost surely, 2^40238021 is an apocalyptic number.

It is an amenable number.

40238021 is a deficient number, since it is larger than the sum of its proper divisors (1).

40238021 is an equidigital number, since it uses as much as digits as its factorization.

40238021 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 40238021 is about 6343.3446225158. The cubic root of 40238021 is about 342.6721985604.

The spelling of 40238021 in words is "forty million, two hundred thirty-eight thousand, twenty-one".