40001987 has 2 divisors, whose sum is σ = 40001988. Its totient is φ = 40001986.

The previous prime is 40001981. The next prime is 40001999. The reversal of 40001987 is 78910004.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 40001987 - 2⁴ = 40001971 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (40001981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20000993 + 20000994.

It is an arithmetic number, because the mean of its divisors is an integer number (20000994).

Almost surely, 2^40001987 is an apocalyptic number.

40001987 is a deficient number, since it is larger than the sum of its proper divisors (1).

40001987 is an equidigital number, since it uses as much as digits as its factorization.

40001987 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2016, while the sum is 29.

The square root of 40001987 is about 6324.7124045288. The cubic root of 40001987 is about 342.0008521119. Note that the first 3 decimals are identical.

It can be divided in two parts, 4000198 and 7, that multiplied together give a triangular number (28001386 = T₇₄₈₃).

The spelling of 40001987 in words is "forty million, one thousand, nine hundred eighty-seven".