21371811 has 8 divisors (see below), whose sum is σ = 29478480. Its totient is φ = 13756512.

The previous prime is 21371809. The next prime is 21371821. The reversal of 21371811 is 11817312.

It is a happy number.

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

It is not a de Polignac number, because 21371811 - 2¹ = 21371809 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21371821) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 122740 + ... + 122913.

It is an arithmetic number, because the mean of its divisors is an integer number (3684810).

Almost surely, 2^21371811 is an apocalyptic number.

21371811 is a deficient number, since it is larger than the sum of its proper divisors (8106669).

21371811 is a wasteful number, since it uses less digits than its factorization.

21371811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 245685.

The product of its digits is 336, while the sum is 24.

The square root of 21371811 is about 4622.9656066209. The cubic root of 21371811 is about 277.5111528672.

The spelling of 21371811 in words is "twenty-one million, three hundred seventy-one thousand, eight hundred eleven".