1381857 has 4 divisors (see below), whose sum is σ = 1842480. Its totient is φ = 921236.

The previous prime is 1381837. The next prime is 1381859. The reversal of 1381857 is 7581831.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 7581831 = 3 ⋅2527277.

It is a cyclic number.

It is not a de Polignac number, because 1381857 - 2¹¹ = 1379809 is a prime.

It is a D-number.

It is not an unprimeable number, because it can be changed into a prime (1381859) 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, 230307 + ... + 230312.

It is an arithmetic number, because the mean of its divisors is an integer number (460620).

2^1381857 is an apocalyptic number.

It is an amenable number.

1381857 is a deficient number, since it is larger than the sum of its proper divisors (460623).

1381857 is an equidigital number, since it uses as much as digits as its factorization.

1381857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 460622.

The product of its digits is 6720, while the sum is 33.

The square root of 1381857 is about 1175.5241384166. The cubic root of 1381857 is about 111.3835445483.

The spelling of 1381857 in words is "one million, three hundred eighty-one thousand, eight hundred fifty-seven".