1379401921 has 4 divisors (see below), whose sum is σ = 1416683092. Its totient is φ = 1342120752.

The previous prime is 1379401889. The next prime is 1379401937. The reversal of 1379401921 is 1291049731.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1291049731 = 23 ⋅56132597.

It can be written as a sum of positive squares in 2 ways, for example, as 885895696 + 493506225 = 29764^2 + 22215^2 .

It is a cyclic number.

It is not a de Polignac number, because 1379401921 - 2⁵ = 1379401889 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37), and also a Moran number because the ratio is a prime number: 37281133 = 1379401921 / (1 + 3 + 7 + 9 + 4 + 0 + 1 + 9 + 2 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1379401951) 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, 18640530 + ... + 18640603.

It is an arithmetic number, because the mean of its divisors is an integer number (354170773).

Almost surely, 2^1379401921 is an apocalyptic number.

It is an amenable number.

1379401921 is a deficient number, since it is larger than the sum of its proper divisors (37281171).

1379401921 is an equidigital number, since it uses as much as digits as its factorization.

1379401921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37281170.

The product of its (nonzero) digits is 13608, while the sum is 37.

The square root of 1379401921 is about 37140.3004968996. The cubic root of 1379401921 is about 1113.1754217949.

The spelling of 1379401921 in words is "one billion, three hundred seventy-nine million, four hundred one thousand, nine hundred twenty-one".