21271955 has 8 divisors (see below), whose sum is σ = 25886304. Its totient is φ = 16777600.

The previous prime is 21271951. The next prime is 21271961. The reversal of 21271955 is 55917212.

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 21271955 - 2² = 21271951 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21271951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29606 + ... + 30315.

It is an arithmetic number, because the mean of its divisors is an integer number (3235788).

Almost surely, 2^21271955 is an apocalyptic number.

21271955 is a deficient number, since it is larger than the sum of its proper divisors (4614349).

21271955 is an equidigital number, since it uses as much as digits as its factorization.

21271955 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59997.

The product of its digits is 6300, while the sum is 32.

The square root of 21271955 is about 4612.1529679749. The cubic root of 21271955 is about 277.0782707475.

The spelling of 21271955 in words is "twenty-one million, two hundred seventy-one thousand, nine hundred fifty-five".