21230511 has 8 divisors (see below), whose sum is σ = 28909824. Its totient is φ = 13852440.

The previous prime is 21230509. The next prime is 21230533. The reversal of 21230511 is 11503212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21230511 - 2¹ = 21230509 is a prime.

It is a super-2 number, since 2×21230511² = 901469194642242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21230551) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 75145 + ... + 75426.

It is an arithmetic number, because the mean of its divisors is an integer number (3613728).

Almost surely, 2^21230511 is an apocalyptic number.

21230511 is a deficient number, since it is larger than the sum of its proper divisors (7679313).

21230511 is a wasteful number, since it uses less digits than its factorization.

21230511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150621.

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

The square root of 21230511 is about 4607.6578649027. The cubic root of 21230511 is about 276.8982105461.

Adding to 21230511 its reverse (11503212), we get a palindrome (32733723).

The spelling of 21230511 in words is "twenty-one million, two hundred thirty thousand, five hundred eleven".