1155551 has 4 divisors (see below), whose sum is σ = 1164504. Its totient is φ = 1146600.

The previous prime is 1155529. The next prime is 1155569. The reversal of 1155551 is 1555511.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1555511 = 19 ⋅81869.

It is a cyclic number.

It is not a de Polignac number, because 1155551 - 2¹⁸ = 893407 is a prime.

It is a super-2 number, since 2×1155551² = 2670596227202, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1155151) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4280 + ... + 4541.

It is an arithmetic number, because the mean of its divisors is an integer number (291126).

2^1155551 is an apocalyptic number.

1155551 is a deficient number, since it is larger than the sum of its proper divisors (8953).

1155551 is an equidigital number, since it uses as much as digits as its factorization.

1155551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8952.

The product of its digits is 625, while the sum is 23.

The square root of 1155551 is about 1074.9655808443. The cubic root of 1155551 is about 104.9372565434.

The spelling of 1155551 in words is "one million, one hundred fifty-five thousand, five hundred fifty-one".