21382870 has 32 divisors (see below), whose sum is σ = 41472000. Its totient is φ = 7914720.

The previous prime is 21382861. The next prime is 21382871. The reversal of 21382870 is 7828312.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21382871) 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, 5631 + ... + 8629.

It is an arithmetic number, because the mean of its divisors is an integer number (1296000).

Almost surely, 2^21382870 is an apocalyptic number.

21382870 is a deficient number, since it is larger than the sum of its proper divisors (20089130).

21382870 is a wasteful number, since it uses less digits than its factorization.

21382870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3060.

The product of its (nonzero) digits is 5376, while the sum is 31.

The square root of 21382870 is about 4624.1615456210. The cubic root of 21382870 is about 277.5590113389.

The spelling of 21382870 in words is "twenty-one million, three hundred eighty-two thousand, eight hundred seventy".