39888921 has 4 divisors (see below), whose sum is σ = 53185232. Its totient is φ = 26592612.

The previous prime is 39888911. The next prime is 39888929. The reversal of 39888921 is 12988893.

It is a happy number.

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: 12988893 = 3 ⋅4329631.

It is not a de Polignac number, because 39888921 - 2¹⁴ = 39872537 is a prime.

It is a super-2 number, since 2×39888921² = 3182252037088482, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (39888929) 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, 6648151 + ... + 6648156.

It is an arithmetic number, because the mean of its divisors is an integer number (13296308).

Almost surely, 2^39888921 is an apocalyptic number.

It is an amenable number.

39888921 is a deficient number, since it is larger than the sum of its proper divisors (13296311).

39888921 is a wasteful number, since it uses less digits than its factorization.

39888921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13296310.

The product of its digits is 248832, while the sum is 48.

The square root of 39888921 is about 6315.7676493044. The cubic root of 39888921 is about 341.6783251491.

It can be divided in two parts, 3988892 and 1, that added together give a palindrome (3988893).

The spelling of 39888921 in words is "thirty-nine million, eight hundred eighty-eight thousand, nine hundred twenty-one".