39969921 has 8 divisors (see below), whose sum is σ = 53564544. Its totient is φ = 26510960.

The previous prime is 39969913. The next prime is 39969949. The reversal of 39969921 is 12996993.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 39969921 - 2³ = 39969913 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (39969961) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33225 + ... + 34406.

It is an arithmetic number, because the mean of its divisors is an integer number (6695568).

Almost surely, 2^39969921 is an apocalyptic number.

It is an amenable number.

39969921 is a deficient number, since it is larger than the sum of its proper divisors (13594623).

39969921 is a wasteful number, since it uses less digits than its factorization.

39969921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67831.

The product of its digits is 236196, while the sum is 48.

The square root of 39969921 is about 6322.1769193847. The cubic root of 39969921 is about 341.9094438948.

It can be divided in two parts, 3996992 and 1, that added together give a palindrome (3996993).

The spelling of 39969921 in words is "thirty-nine million, nine hundred sixty-nine thousand, nine hundred twenty-one".