1396394721 has 40 divisors (see below), whose sum is σ = 2266668800. Its totient is φ = 853454880.

The previous prime is 1396394717. The next prime is 1396394723. The reversal of 1396394721 is 1274936931.

1396394721 is a `hidden beast` number, since 1 + 3 + 9 + 639 + 4 + 7 + 2 + 1 = 666.

1396394721 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 1396394721 - 2² = 1396394717 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1396394723) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 33075 + ... + 62343.

It is an arithmetic number, because the mean of its divisors is an integer number (56666720).

Almost surely, 2^1396394721 is an apocalyptic number.

It is an amenable number.

1396394721 is a deficient number, since it is larger than the sum of its proper divisors (870274079).

1396394721 is a wasteful number, since it uses less digits than its factorization.

1396394721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29331 (or 29322 counting only the distinct ones).

The product of its digits is 244944, while the sum is 45.

The square root of 1396394721 is about 37368.3652438797. The cubic root of 1396394721 is about 1117.7278342724.

The spelling of 1396394721 in words is "one billion, three hundred ninety-six million, three hundred ninety-four thousand, seven hundred twenty-one".