21151230 has 64 divisors (see below), whose sum is σ = 54639360. Its totient is φ = 5220864.

The previous prime is 21151219. The next prime is 21151241. The reversal of 21151230 is 3215112.

It is an interprime number because it is at equal distance from previous prime (21151219) and next prime (21151241).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 33861 + ... + 34479.

It is an arithmetic number, because the mean of its divisors is an integer number (853740).

Almost surely, 2^21151230 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21151230, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27319680).

21151230 is an abundant number, since it is smaller than the sum of its proper divisors (33488130).

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

21151230 is a wasteful number, since it uses less digits than its factorization.

21151230 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 713.

The product of its (nonzero) digits is 60, while the sum is 15.

The square root of 21151230 is about 4599.0466403375. The cubic root of 21151230 is about 276.5531073768.

Adding to 21151230 its reverse (3215112), we get a palindrome (24366342).

The spelling of 21151230 in words is "twenty-one million, one hundred fifty-one thousand, two hundred thirty".