21229375 has 10 divisors (see below), whose sum is σ = 26529008. Its totient is φ = 16983000.

The previous prime is 21229361. The next prime is 21229387. The reversal of 21229375 is 57392212.

It is a de Polignac number, because none of the positive numbers 2^k-21229375 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 16359 + ... + 17608.

Almost surely, 2^21229375 is an apocalyptic number.

21229375 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21229375 is a deficient number, since it is larger than the sum of its proper divisors (5299633).

21229375 is an frugal number, since it uses more digits than its factorization.

21229375 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33987 (or 33972 counting only the distinct ones).

The product of its digits is 7560, while the sum is 31.

The square root of 21229375 is about 4607.5345902120. The cubic root of 21229375 is about 276.8932717111.

The spelling of 21229375 in words is "twenty-one million, two hundred twenty-nine thousand, three hundred seventy-five".