1390821 has 8 divisors (see below), whose sum is σ = 1963584. Its totient is φ = 872640.

The previous prime is 1390813. The next prime is 1390841. The reversal of 1390821 is 1280931.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1390821 - 2³ = 1390813 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1390791 and 1390800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1390801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13585 + ... + 13686.

It is an arithmetic number, because the mean of its divisors is an integer number (245448).

2^1390821 is an apocalyptic number.

It is an amenable number.

1390821 is a deficient number, since it is larger than the sum of its proper divisors (572763).

1390821 is a wasteful number, since it uses less digits than its factorization.

1390821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27291.

The product of its (nonzero) digits is 432, while the sum is 24.

The square root of 1390821 is about 1179.3307424128. The cubic root of 1390821 is about 111.6238711285.

It can be divided in two parts, 1390 and 821, that added together give a triangular number (2211 = T₆₆).

The spelling of 1390821 in words is "one million, three hundred ninety thousand, eight hundred twenty-one".