21311154 has 32 divisors (see below), whose sum is σ = 48168000. Its totient is φ = 6982272.

The previous prime is 21311137. The next prime is 21311161. The reversal of 21311154 is 45111312.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 159 + ... + 6530.

It is an arithmetic number, because the mean of its divisors is an integer number (1505250).

Almost surely, 2^21311154 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21311154, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24084000).

21311154 is an abundant number, since it is smaller than the sum of its proper divisors (26856846).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21311154 is a wasteful number, since it uses less digits than its factorization.

21311154 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6759 (or 6753 counting only the distinct ones).

The product of its digits is 120, while the sum is 18.

The square root of 21311154 is about 4616.4005458799. The cubic root of 21311154 is about 277.2483620947.

Adding to 21311154 its reverse (45111312), we get a palindrome (66422466).

The spelling of 21311154 in words is "twenty-one million, three hundred eleven thousand, one hundred fifty-four".