21275710 has 32 divisors (see below), whose sum is σ = 39204000. Its totient is φ = 8311680.

The previous prime is 21275707. The next prime is 21275711. The reversal of 21275710 is 1757212.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21275711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 142716 + ... + 142864.

It is an arithmetic number, because the mean of its divisors is an integer number (1225125).

Almost surely, 2^21275710 is an apocalyptic number.

21275710 is a deficient number, since it is larger than the sum of its proper divisors (17928290).

21275710 is a wasteful number, since it uses less digits than its factorization.

21275710 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 396.

The product of its (nonzero) digits is 980, while the sum is 25.

The square root of 21275710 is about 4612.5600267097. The cubic root of 21275710 is about 277.0945733972.

The spelling of 21275710 in words is "twenty-one million, two hundred seventy-five thousand, seven hundred ten".