39940521 has 4 divisors (see below), whose sum is σ = 53254032. Its totient is φ = 26627012.

The previous prime is 39940487. The next prime is 39940529. The reversal of 39940521 is 12504993.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12504993 = 3 ⋅4168331.

It is a cyclic number.

It is not a de Polignac number, because 39940521 - 2⁹ = 39940009 is a prime.

It is not an unprimeable number, because it can be changed into a prime (39940529) 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, 6656751 + ... + 6656756.

It is an arithmetic number, because the mean of its divisors is an integer number (13313508).

Almost surely, 2^39940521 is an apocalyptic number.

It is an amenable number.

39940521 is a deficient number, since it is larger than the sum of its proper divisors (13313511).

39940521 is a wasteful number, since it uses less digits than its factorization.

39940521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13313510.

The product of its (nonzero) digits is 9720, while the sum is 33.

The square root of 39940521 is about 6319.8513431884. The cubic root of 39940521 is about 341.8255924799.

Subtracting from 39940521 its reverse (12504993), we obtain a triangular number (27435528 = T₇₄₀₇).

The spelling of 39940521 in words is "thirty-nine million, nine hundred forty thousand, five hundred twenty-one".