21070870 has 8 divisors (see below), whose sum is σ = 37927584. Its totient is φ = 8428344.

The previous prime is 21070859. The next prime is 21070873. The reversal of 21070870 is 7807012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-3 number, since 3×21070870³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21070873) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1053534 + ... + 1053553.

It is an arithmetic number, because the mean of its divisors is an integer number (4740948).

Almost surely, 2^21070870 is an apocalyptic number.

21070870 is a deficient number, since it is larger than the sum of its proper divisors (16856714).

21070870 is a wasteful number, since it uses less digits than its factorization.

21070870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2107094.

The product of its (nonzero) digits is 784, while the sum is 25.

The square root of 21070870 is about 4590.3017330019. The cubic root of 21070870 is about 276.2024262378.

Adding to 21070870 its reverse (7807012), we get a palindrome (28877882).

The spelling of 21070870 in words is "twenty-one million, seventy thousand, eight hundred seventy".