981551 has 4 divisors (see below), whose sum is σ = 997704. Its totient is φ = 965400.

The previous prime is 981527. The next prime is 981569. The reversal of 981551 is 155189.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 155189 = 311 ⋅499.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-981551 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (981151) 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, 7985 + ... + 8106.

It is an arithmetic number, because the mean of its divisors is an integer number (249426).

2⁹⁸¹⁵⁵¹ is an apocalyptic number.

981551 is a deficient number, since it is larger than the sum of its proper divisors (16153).

981551 is a wasteful number, since it uses less digits than its factorization.

981551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16152.

The product of its digits is 1800, while the sum is 29.

The square root of 981551 is about 990.7325572525. The cubic root of 981551 is about 99.3812122483.

The spelling of 981551 in words is "nine hundred eighty-one thousand, five hundred fifty-one".