21217254 has 16 divisors (see below), whose sum is σ = 43470000. Its totient is φ = 6899840.

The previous prime is 21217249. The next prime is 21217271. The reversal of 21217254 is 45271212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42879 + ... + 43370.

It is an arithmetic number, because the mean of its divisors is an integer number (2716875).

Almost surely, 2^21217254 is an apocalyptic number.

21217254 is an abundant number, since it is smaller than the sum of its proper divisors (22252746).

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

21217254 is a wasteful number, since it uses less digits than its factorization.

21217254 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86295.

The product of its digits is 1120, while the sum is 24.

The square root of 21217254 is about 4606.2190568839. The cubic root of 21217254 is about 276.8405638900.

Adding to 21217254 its reverse (45271212), we get a palindrome (66488466).

It can be divided in two parts, 212172 and 54, that added together give a triangular number (212226 = T₆₅₁).

The spelling of 21217254 in words is "twenty-one million, two hundred seventeen thousand, two hundred fifty-four".