21212475 has 12 divisors (see below), whose sum is σ = 35071416. Its totient is φ = 11313280.

The previous prime is 21212467. The next prime is 21212483. The reversal of 21212475 is 57421212.

It is an interprime number because it is at equal distance from previous prime (21212467) and next prime (21212483).

It is not a de Polignac number, because 21212475 - 2³ = 21212467 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 141342 + ... + 141491.

It is an arithmetic number, because the mean of its divisors is an integer number (2922618).

Almost surely, 2^21212475 is an apocalyptic number.

21212475 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21212475 is a deficient number, since it is larger than the sum of its proper divisors (13858941).

21212475 is a wasteful number, since it uses less digits than its factorization.

21212475 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 282846 (or 282841 counting only the distinct ones).

The product of its digits is 1120, while the sum is 24.

The square root of 21212475 is about 4605.7002724884. The cubic root of 21212475 is about 276.8197770278.

Adding to 21212475 its reverse (57421212), we get a palindrome (78633687).

The spelling of 21212475 in words is "twenty-one million, two hundred twelve thousand, four hundred seventy-five".