1397491921 has 8 divisors (see below), whose sum is σ = 1602586944. Its totient is φ = 1193760240.

The previous prime is 1397491889. The next prime is 1397491981. The reversal of 1397491921 is 1291947931.

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 1397491921 - 2⁵ = 1397491889 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1397491981) 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, 338635 + ... + 342736.

It is an arithmetic number, because the mean of its divisors is an integer number (200323368).

Almost surely, 2^1397491921 is an apocalyptic number.

It is an amenable number.

1397491921 is a deficient number, since it is larger than the sum of its proper divisors (205095023).

1397491921 is an equidigital number, since it uses as much as digits as its factorization.

1397491921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 681671.

The product of its digits is 122472, while the sum is 46.

The square root of 1397491921 is about 37383.0432281803. The cubic root of 1397491921 is about 1118.0205046040.

The spelling of 1397491921 in words is "one billion, three hundred ninety-seven million, four hundred ninety-one thousand, nine hundred twenty-one".