21253877 has 8 divisors (see below), whose sum is σ = 21631680. Its totient is φ = 20878560.

The previous prime is 21253871. The next prime is 21253889. The reversal of 21253877 is 77835212.

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 21253877 - 2⁴ = 21253861 is a prime.

It is a super-2 number, since 2×21253877² = 903454575062258, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21253871) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25802 + ... + 26612.

It is an arithmetic number, because the mean of its divisors is an integer number (2703960).

Almost surely, 2^21253877 is an apocalyptic number.

It is an amenable number.

21253877 is a deficient number, since it is larger than the sum of its proper divisors (377803).

21253877 is an equidigital number, since it uses as much as digits as its factorization.

21253877 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1243.

The product of its digits is 23520, while the sum is 35.

The square root of 21253877 is about 4610.1927291600. The cubic root of 21253877 is about 276.9997567193. Note that the first 3 decimals are identical.

The spelling of 21253877 in words is "twenty-one million, two hundred fifty-three thousand, eight hundred seventy-seven".