1551421 has 4 divisors (see below), whose sum is σ = 1573344. Its totient is φ = 1529500.

The previous prime is 1551383. The next prime is 1551449. The reversal of 1551421 is 1241551.

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.

It is a cyclic number.

It is not a de Polignac number, because 1551421 - 2¹³ = 1543229 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561421) 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 3 ways as a sum of consecutive naturals, for example, 10855 + ... + 10996.

It is an arithmetic number, because the mean of its divisors is an integer number (393336).

2^1551421 is an apocalyptic number.

It is an amenable number.

1551421 is a deficient number, since it is larger than the sum of its proper divisors (21923).

1551421 is an equidigital number, since it uses as much as digits as its factorization.

1551421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21922.

The product of its digits is 200, while the sum is 19.

The square root of 1551421 is about 1245.5605163941. The cubic root of 1551421 is about 115.7648078495.

Adding to 1551421 its reverse (1241551), we get a palindrome (2792972).

The spelling of 1551421 in words is "one million, five hundred fifty-one thousand, four hundred twenty-one".