21752830 has 16 divisors (see below), whose sum is σ = 42714864. Its totient is φ = 7910080.

The previous prime is 21752791. The next prime is 21752831. The reversal of 21752830 is 3825712.

It is a super-2 number, since 2×21752830² = 946371226017800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21752831) 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, 98767 + ... + 98986.

It is an arithmetic number, because the mean of its divisors is an integer number (2669679).

Almost surely, 2^21752830 is an apocalyptic number.

21752830 is a deficient number, since it is larger than the sum of its proper divisors (20962034).

21752830 is a wasteful number, since it uses less digits than its factorization.

21752830 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 197771.

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 21752830 is about 4663.9929245229. The cubic root of 21752830 is about 279.1506147549.

It can be divided in two parts, 2175 and 2830, that added together give a palindrome (5005).

The spelling of 21752830 in words is "twenty-one million, seven hundred fifty-two thousand, eight hundred thirty".