21254723 has 8 divisors (see below), whose sum is σ = 24584448. Its totient is φ = 17998344.

The previous prime is 21254707. The next prime is 21254729. The reversal of 21254723 is 32745212.

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

It is not a de Polignac number, because 21254723 - 2⁴ = 21254707 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a junction number, because it is equal to n+sod(n) for n = 21254692 and 21254701.

It is not an unprimeable number, because it can be changed into a prime (21254729) 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, 17711 + ... + 18872.

It is an arithmetic number, because the mean of its divisors is an integer number (3073056).

Almost surely, 2^21254723 is an apocalyptic number.

21254723 is a deficient number, since it is larger than the sum of its proper divisors (3329725).

21254723 is an equidigital number, since it uses as much as digits as its factorization.

21254723 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36673.

The product of its digits is 3360, while the sum is 26.

The square root of 21254723 is about 4610.2844814610. The cubic root of 21254723 is about 277.0034319497.

Adding to 21254723 its reverse (32745212), we get a palindrome (53999935).

The spelling of 21254723 in words is "twenty-one million, two hundred fifty-four thousand, seven hundred twenty-three".