396165721 has 8 divisors (see below), whose sum is σ = 453772800. Its totient is φ = 338811648.

The previous prime is 396165719. The next prime is 396165727. The reversal of 396165721 is 127561693.

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

It is not a de Polignac number, because 396165721 - 2¹ = 396165719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (396165727) 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, 59881 + ... + 66166.

It is an arithmetic number, because the mean of its divisors is an integer number (56721600).

Almost surely, 2^396165721 is an apocalyptic number.

It is an amenable number.

396165721 is a deficient number, since it is larger than the sum of its proper divisors (57607079).

396165721 is a wasteful number, since it uses less digits than its factorization.

396165721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126503.

The product of its digits is 68040, while the sum is 40.

The square root of 396165721 is about 19903.9122033835. The cubic root of 396165721 is about 734.4444695435. Note that the first 4 decimals are identical.

The spelling of 396165721 in words is "three hundred ninety-six million, one hundred sixty-five thousand, seven hundred twenty-one".