39721381 has 16 divisors (see below), whose sum is σ = 48274560. Its totient is φ = 31924800.

The previous prime is 39721373. The next prime is 39721397. The reversal of 39721381 is 18312793.

39721381 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 39721381 - 2³ = 39721373 is a prime.

It is a super-2 number, since 2×39721381² = 3155576217094322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39721351) 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 15 ways as a sum of consecutive naturals, for example, 11955 + ... + 14911.

It is an arithmetic number, because the mean of its divisors is an integer number (3017160).

Almost surely, 2^39721381 is an apocalyptic number.

It is an amenable number.

39721381 is a deficient number, since it is larger than the sum of its proper divisors (8553179).

39721381 is a wasteful number, since it uses less digits than its factorization.

39721381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3084.

The product of its digits is 9072, while the sum is 34.

The square root of 39721381 is about 6302.4900634590. The cubic root of 39721381 is about 341.1992855351.

The spelling of 39721381 in words is "thirty-nine million, seven hundred twenty-one thousand, three hundred eighty-one".