21790071 has 6 divisors (see below), whose sum is σ = 31474560. Its totient is φ = 14526708.

The previous prime is 21790051. The next prime is 21790079. The reversal of 21790071 is 17009712.

It is not a de Polignac number, because 21790071 - 2⁶ = 21790007 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21790079) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1210551 + ... + 1210568.

It is an arithmetic number, because the mean of its divisors is an integer number (5245760).

Almost surely, 2^21790071 is an apocalyptic number.

21790071 is a deficient number, since it is larger than the sum of its proper divisors (9684489).

21790071 is a wasteful number, since it uses less digits than its factorization.

21790071 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2421125 (or 2421122 counting only the distinct ones).

The product of its (nonzero) digits is 882, while the sum is 27.

The square root of 21790071 is about 4667.9836117964. The cubic root of 21790071 is about 279.3098265462.

Adding to 21790071 its reverse (17009712), we get a palindrome (38799783).

The spelling of 21790071 in words is "twenty-one million, seven hundred ninety thousand, seventy-one".