21530151 has 32 divisors (see below), whose sum is σ = 34099200. Its totient is φ = 13396320.

The previous prime is 21530147. The next prime is 21530153. The reversal of 21530151 is 15103512.

It is not a de Polignac number, because 21530151 - 2² = 21530147 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21530153) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 23830 + ... + 24716.

It is an arithmetic number, because the mean of its divisors is an integer number (1065600).

Almost surely, 2^21530151 is an apocalyptic number.

21530151 is a deficient number, since it is larger than the sum of its proper divisors (12569049).

21530151 is a wasteful number, since it uses less digits than its factorization.

21530151 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 956 (or 950 counting only the distinct ones).

The product of its (nonzero) digits is 150, while the sum is 18.

The square root of 21530151 is about 4640.0593746201. The cubic root of 21530151 is about 278.1948110914.

Adding to 21530151 its reverse (15103512), we get a palindrome (36633663).

The spelling of 21530151 in words is "twenty-one million, five hundred thirty thousand, one hundred fifty-one".