39742821 has 24 divisors (see below), whose sum is σ = 61026264. Its totient is φ = 24837120.

The previous prime is 39742819. The next prime is 39742831. The reversal of 39742821 is 12824793.

It can be written as a sum of positive squares in 4 ways, for example, as 617796 + 39125025 = 786^2 + 6255^2 .

It is not a de Polignac number, because 39742821 - 2¹ = 39742819 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39742811) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 64105 + ... + 64721.

It is an arithmetic number, because the mean of its divisors is an integer number (2542761).

Almost surely, 2^39742821 is an apocalyptic number.

It is an amenable number.

39742821 is a deficient number, since it is larger than the sum of its proper divisors (21283443).

39742821 is a wasteful number, since it uses less digits than its factorization.

39742821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1061 (or 1058 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 39742821 is about 6304.1907490177. The cubic root of 39742821 is about 341.2606630327.

The spelling of 39742821 in words is "thirty-nine million, seven hundred forty-two thousand, eight hundred twenty-one".