39661381 has 4 divisors (see below), whose sum is σ = 40220064. Its totient is φ = 39102700.

The previous prime is 39661367. The next prime is 39661399. The reversal of 39661381 is 18316693.

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.

It is a cyclic number.

It is not a de Polignac number, because 39661381 - 2¹³ = 39653189 is a prime.

It is a super-2 number, since 2×39661381² = 3146050285654322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 39661381.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39661481) 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, 279235 + ... + 279376.

It is an arithmetic number, because the mean of its divisors is an integer number (10055016).

Almost surely, 2^39661381 is an apocalyptic number.

It is an amenable number.

39661381 is a deficient number, since it is larger than the sum of its proper divisors (558683).

39661381 is an equidigital number, since it uses as much as digits as its factorization.

39661381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 558682.

The product of its digits is 23328, while the sum is 37.

The square root of 39661381 is about 6297.7282411994. The cubic root of 39661381 is about 341.0274026763.

The spelling of 39661381 in words is "thirty-nine million, six hundred sixty-one thousand, three hundred eighty-one".