21251052 has 24 divisors (see below), whose sum is σ = 55095600. Its totient is φ = 7083648.

The previous prime is 21251023. The next prime is 21251053. The reversal of 21251052 is 25015212.

It is a super-2 number, since 2×21251052² = 903214422213408, which contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (21251053) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 98277 + ... + 98492.

It is an arithmetic number, because the mean of its divisors is an integer number (2295650).

Almost surely, 2^21251052 is an apocalyptic number.

It is an amenable number.

21251052 is an abundant number, since it is smaller than the sum of its proper divisors (33844548).

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

21251052 is a wasteful number, since it uses less digits than its factorization.

21251052 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196782 (or 196774 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 18.

The square root of 21251052 is about 4609.8863326551. The cubic root of 21251052 is about 276.9874835235.

Adding to 21251052 its reverse (25015212), we get a palindrome (46266264).

The spelling of 21251052 in words is "twenty-one million, two hundred fifty-one thousand, fifty-two".