1399981 has 4 divisors (see below), whose sum is σ = 1527264. Its totient is φ = 1272700.

The previous prime is 1399963. The next prime is 1399999. The reversal of 1399981 is 1899931.

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: 1899931 = 11 ⋅172721.

It is an interprime number because it is at equal distance from previous prime (1399963) and next prime (1399999).

It is not a de Polignac number, because 1399981 - 2⁹ = 1399469 is a prime.

It is a super-2 number, since 2×1399981² = 3919893600722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1399381) 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, 63625 + ... + 63646.

It is an arithmetic number, because the mean of its divisors is an integer number (381816).

2^1399981 is an apocalyptic number.

1399981 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1399981 is a deficient number, since it is larger than the sum of its proper divisors (127283).

1399981 is a wasteful number, since it uses less digits than its factorization.

1399981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127282.

The product of its digits is 17496, while the sum is 40.

The square root of 1399981 is about 1183.2079276273. The cubic root of 1399981 is about 111.8683881323.

The spelling of 1399981 in words is "one million, three hundred ninety-nine thousand, nine hundred eighty-one".