21121254 has 96 divisors (see below), whose sum is σ = 58406400. Its totient is φ = 5468400.

The previous prime is 21121253. The next prime is 21121271. The reversal of 21121254 is 45212112.

It is a super-2 number, since 2×21121254² = 892214741065032, which contains 22 as substring.

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

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121253) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 67759 + ... + 68069.

It is an arithmetic number, because the mean of its divisors is an integer number (608400).

Almost surely, 2^21121254 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21121254, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29203200).

21121254 is an abundant number, since it is smaller than the sum of its proper divisors (37285146).

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

21121254 is a wasteful number, since it uses less digits than its factorization.

21121254 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 351 (or 334 counting only the distinct ones).

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

The square root of 21121254 is about 4595.7865485682. The cubic root of 21121254 is about 276.4223998439.

Adding to 21121254 its reverse (45212112), we get a palindrome (66333366).

The spelling of 21121254 in words is "twenty-one million, one hundred twenty-one thousand, two hundred fifty-four".