1399681 has 8 divisors (see below), whose sum is σ = 1458944. Its totient is φ = 1341360.

The previous prime is 1399679. The next prime is 1399687. The reversal of 1399681 is 1869931.

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 1399681 - 2¹ = 1399679 is a prime.

It is a super-2 number, since 2×1399681² = 3918213803522, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

1399681 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 1399681.

It is not an unprimeable number, because it can be changed into a prime (1399687) 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, 4915 + ... + 5191.

It is an arithmetic number, because the mean of its divisors is an integer number (182368).

2^1399681 is an apocalyptic number.

It is an amenable number.

1399681 is a deficient number, since it is larger than the sum of its proper divisors (59263).

1399681 is a wasteful number, since it uses less digits than its factorization.

1399681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 471.

The product of its digits is 11664, while the sum is 37.

The square root of 1399681 is about 1183.0811468365. The cubic root of 1399681 is about 111.8603968538.

It can be divided in two parts, 1399 and 681, that added together give a triangular number (2080 = T₆₄).

The spelling of 1399681 in words is "one million, three hundred ninety-nine thousand, six hundred eighty-one".