21448031 has 4 divisors (see below), whose sum is σ = 23397864. Its totient is φ = 19498200.

The previous prime is 21448003. The next prime is 21448051. The reversal of 21448031 is 13084412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21448031 - 2¹⁰ = 21447007 is a prime.

It is a super-2 number, since 2×21448031² = 920036067553922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21447988 and 21448006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21448051) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 974900 + ... + 974921.

It is an arithmetic number, because the mean of its divisors is an integer number (5849466).

Almost surely, 2^21448031 is an apocalyptic number.

21448031 is a deficient number, since it is larger than the sum of its proper divisors (1949833).

21448031 is a wasteful number, since it uses less digits than its factorization.

21448031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1949832.

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 21448031 is about 4631.2018958365. The cubic root of 21448031 is about 277.8406648669.

The spelling of 21448031 in words is "twenty-one million, four hundred forty-eight thousand, thirty-one".