40438691 has 2 divisors, whose sum is σ = 40438692. Its totient is φ = 40438690.

The previous prime is 40438687. The next prime is 40438703. The reversal of 40438691 is 19683404.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 40438691 - 2² = 40438687 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (40438681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20219345 + 20219346.

It is an arithmetic number, because the mean of its divisors is an integer number (20219346).

Almost surely, 2^40438691 is an apocalyptic number.

40438691 is a deficient number, since it is larger than the sum of its proper divisors (1).

40438691 is an equidigital number, since it uses as much as digits as its factorization.

40438691 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20736, while the sum is 35.

The square root of 40438691 is about 6359.1423163820. The cubic root of 40438691 is about 343.2408981269.

The spelling of 40438691 in words is "forty million, four hundred thirty-eight thousand, six hundred ninety-one".