21451273 has 8 divisors (see below), whose sum is σ = 21964608. Its totient is φ = 20942064.

The previous prime is 21451237. The next prime is 21451277. The reversal of 21451273 is 37215412.

It is a happy number.

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 21451273 - 2⁹ = 21450761 is a prime.

It is a super-2 number, since 2×21451273² = 920314226641058, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21451277) 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, 11140 + ... + 12922.

It is an arithmetic number, because the mean of its divisors is an integer number (2745576).

Almost surely, 2^21451273 is an apocalyptic number.

It is an amenable number.

21451273 is a deficient number, since it is larger than the sum of its proper divisors (513335).

21451273 is a wasteful number, since it uses less digits than its factorization.

21451273 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2063.

The product of its digits is 1680, while the sum is 25.

The square root of 21451273 is about 4631.5518997416. The cubic root of 21451273 is about 277.8546632623.

Adding to 21451273 its reverse (37215412), we get a palindrome (58666685).

The spelling of 21451273 in words is "twenty-one million, four hundred fifty-one thousand, two hundred seventy-three".