40668021 has 8 divisors (see below), whose sum is σ = 60248960. Its totient is φ = 27111996.

The previous prime is 40667993. The next prime is 40668059. The reversal of 40668021 is 12086604.

It is not a de Polignac number, because 40668021 - 2¹⁷ = 40536949 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 1506223 = 40668021 / (4 + 0 + 6 + 6 + 8 + 0 + 2 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40668421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 753085 + ... + 753138.

It is an arithmetic number, because the mean of its divisors is an integer number (7531120).

Almost surely, 2^40668021 is an apocalyptic number.

It is an amenable number.

40668021 is a deficient number, since it is larger than the sum of its proper divisors (19580939).

40668021 is a wasteful number, since it uses less digits than its factorization.

40668021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1506232 (or 1506226 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 40668021 is about 6377.1483438916. The cubic root of 40668021 is about 343.8885213184. Note that the first 3 decimals are identical.

The spelling of 40668021 in words is "forty million, six hundred sixty-eight thousand, twenty-one".