21154122 has 56 divisors (see below), whose sum is σ = 51939360. Its totient is φ = 6405480.

The previous prime is 21154109. The next prime is 21154123. The reversal of 21154122 is 22145112.

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

It is a junction number, because it is equal to n+sod(n) for n = 21154095 and 21154104.

It is not an unprimeable number, because it can be changed into a prime (21154123) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 15379 + ... + 16697.

Almost surely, 2^21154122 is an apocalyptic number.

21154122 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 21154122, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25969680).

21154122 is an abundant number, since it is smaller than the sum of its proper divisors (30785238).

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

21154122 is a wasteful number, since it uses less digits than its factorization.

21154122 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1350 (or 1335 counting only the distinct ones).

The product of its digits is 160, while the sum is 18.

The square root of 21154122 is about 4599.3610425797. The cubic root of 21154122 is about 276.5657111377.

Adding to 21154122 its reverse (22145112), we get a palindrome (43299234).

The spelling of 21154122 in words is "twenty-one million, one hundred fifty-four thousand, one hundred twenty-two".