21630075 has 48 divisors (see below), whose sum is σ = 38628480. Its totient is φ = 10644480.

The previous prime is 21630071. The next prime is 21630101. The reversal of 21630075 is 57003612.

It is not a de Polignac number, because 21630075 - 2² = 21630071 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21630071) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 61099 + ... + 61451.

It is an arithmetic number, because the mean of its divisors is an integer number (804760).

Almost surely, 2^21630075 is an apocalyptic number.

21630075 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21630075 is a deficient number, since it is larger than the sum of its proper divisors (16998405).

21630075 is a wasteful number, since it uses less digits than its factorization.

21630075 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 428 (or 423 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 24.

The square root of 21630075 is about 4650.8144448043. The cubic root of 21630075 is about 278.6245254288.

Adding to 21630075 its reverse (57003612), we get a palindrome (78633687).

The spelling of 21630075 in words is "twenty-one million, six hundred thirty thousand, seventy-five".