21638071 has 8 divisors (see below), whose sum is σ = 26631584. Its totient is φ = 17120160.

The previous prime is 21638069. The next prime is 21638117. The reversal of 21638071 is 17083612.

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

It is a cyclic number.

It is not a de Polignac number, because 21638071 - 2¹ = 21638069 is a prime.

It is a super-2 number, since 2×21638071² = 936412233202082, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21638041) 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, 118800 + ... + 118981.

It is an arithmetic number, because the mean of its divisors is an integer number (3328948).

Almost surely, 2^21638071 is an apocalyptic number.

21638071 is a deficient number, since it is larger than the sum of its proper divisors (4993513).

21638071 is a wasteful number, since it uses less digits than its factorization.

21638071 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 237801.

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 21638071 is about 4651.6739997554. The cubic root of 21638071 is about 278.6588542855.

The spelling of 21638071 in words is "twenty-one million, six hundred thirty-eight thousand, seventy-one".