1321551 has 24 divisors (see below), whose sum is σ = 2381184. Its totient is φ = 686160.

The previous prime is 1321549. The next prime is 1321571. The reversal of 1321551 is 1551231.

It is not a de Polignac number, because 1321551 - 2¹ = 1321549 is a prime.

It is a super-3 number, since 3×1321551³ = 6924254751333141453, which contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1321571) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 261 + ... + 1646.

It is an arithmetic number, because the mean of its divisors is an integer number (99216).

2^1321551 is an apocalyptic number.

1321551 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1321551 is a deficient number, since it is larger than the sum of its proper divisors (1059633).

1321551 is a wasteful number, since it uses less digits than its factorization.

1321551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1931 (or 1928 counting only the distinct ones).

The product of its digits is 150, while the sum is 18.

The square root of 1321551 is about 1149.5873172578. The cubic root of 1321551 is about 109.7390785499.

Adding to 1321551 its reverse (1551231), we get a palindrome (2872782).

The spelling of 1321551 in words is "one million, three hundred twenty-one thousand, five hundred fifty-one".