40120021 has 4 divisors (see below), whose sum is σ = 41503500. Its totient is φ = 38736544.

The previous prime is 40120009. The next prime is 40120033. The reversal of 40120021 is 12002104.

40120021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (40120009) and next prime (40120033).

It can be written as a sum of positive squares in 2 ways, for example, as 10797796 + 29322225 = 3286^2 + 5415^2 .

It is a cyclic number.

It is not a de Polignac number, because 40120021 - 2¹³ = 40111829 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40120081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 691696 + ... + 691753.

It is an arithmetic number, because the mean of its divisors is an integer number (10375875).

Almost surely, 2^40120021 is an apocalyptic number.

It is an amenable number.

40120021 is a deficient number, since it is larger than the sum of its proper divisors (1383479).

40120021 is a wasteful number, since it uses less digits than its factorization.

40120021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1383478.

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 40120021 is about 6334.0367065561. The cubic root of 40120021 is about 342.3369028281.

Adding to 40120021 its reverse (12002104), we get a palindrome (52122125).

The spelling of 40120021 in words is "forty million, one hundred twenty thousand, twenty-one".