1691421 has 8 divisors (see below), whose sum is σ = 2268960. Its totient is φ = 1120752.

The previous prime is 1691419. The next prime is 1691423. The reversal of 1691421 is 1241961.

It is an interprime number because it is at equal distance from previous prime (1691419) and next prime (1691423).

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

It is not a de Polignac number, because 1691421 - 2¹ = 1691419 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1691391 and 1691400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1691423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1111 + ... + 2148.

It is an arithmetic number, because the mean of its divisors is an integer number (283620).

2^1691421 is an apocalyptic number.

It is an amenable number.

1691421 is a deficient number, since it is larger than the sum of its proper divisors (577539).

1691421 is a wasteful number, since it uses less digits than its factorization.

1691421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3435.

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

The square root of 1691421 is about 1300.5464236235. The cubic root of 1691421 is about 119.1472179344.

It can be divided in two parts, 1691 and 421, that added together give a palindrome (2112).

The spelling of 1691421 in words is "one million, six hundred ninety-one thousand, four hundred twenty-one".