39921940 has 12 divisors (see below), whose sum is σ = 83836116. Its totient is φ = 15968768.

The previous prime is 39921911. The next prime is 39921943. The reversal of 39921940 is 4912993.

It can be written as a sum of positive squares in 2 ways, for example, as 29463184 + 10458756 = 5428^2 + 3234^2 .

It is a super-2 number, since 2×39921940² = 3187522586727200, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 39921940.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39921943) 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, 998029 + ... + 998068.

It is an arithmetic number, because the mean of its divisors is an integer number (6986343).

Almost surely, 2^39921940 is an apocalyptic number.

It is an amenable number.

39921940 is an abundant number, since it is smaller than the sum of its proper divisors (43914176).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

39921940 is a wasteful number, since it uses less digits than its factorization.

39921940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1996106 (or 1996104 counting only the distinct ones).

The product of its (nonzero) digits is 17496, while the sum is 37.

The square root of 39921940 is about 6318.3811217748. The cubic root of 39921940 is about 341.7725765922.

The spelling of 39921940 in words is "thirty-nine million, nine hundred twenty-one thousand, nine hundred forty".