21247270 has 32 divisors (see below), whose sum is σ = 41951520. Its totient is φ = 7683840.

The previous prime is 21247267. The next prime is 21247271. The reversal of 21247270 is 7274212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21247271) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25216 + ... + 26044.

It is an arithmetic number, because the mean of its divisors is an integer number (1310985).

Almost surely, 2^21247270 is an apocalyptic number.

21247270 is a deficient number, since it is larger than the sum of its proper divisors (20704250).

21247270 is a wasteful number, since it uses less digits than its factorization.

21247270 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1080.

The product of its (nonzero) digits is 1568, while the sum is 25.

The square root of 21247270 is about 4609.4761090606. The cubic root of 21247270 is about 276.9710509438.

The spelling of 21247270 in words is "twenty-one million, two hundred forty-seven thousand, two hundred seventy".