40247021 has 4 divisors (see below), whose sum is σ = 41545344. Its totient is φ = 38948700.

The previous prime is 40246991. The next prime is 40247047. The reversal of 40247021 is 12074204.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-40247021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 40246984 and 40247002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40247071) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 649115 + ... + 649176.

It is an arithmetic number, because the mean of its divisors is an integer number (10386336).

Almost surely, 2^40247021 is an apocalyptic number.

It is an amenable number.

40247021 is a deficient number, since it is larger than the sum of its proper divisors (1298323).

40247021 is a wasteful number, since it uses less digits than its factorization.

40247021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1298322.

The product of its (nonzero) digits is 448, while the sum is 20.

The square root of 40247021 is about 6344.0539877905. The cubic root of 40247021 is about 342.6977450444.

The spelling of 40247021 in words is "forty million, two hundred forty-seven thousand, twenty-one".