21250723 has 8 divisors (see below), whose sum is σ = 22932000. Its totient is φ = 19576128.

The previous prime is 21250709. The next prime is 21250771. The reversal of 21250723 is 32705212.

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

It is not a de Polignac number, because 21250723 - 2⁹ = 21250211 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 = 21250694 and 21250703.

It is not an unprimeable number, because it can be changed into a prime (21250793) 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, 6423 + ... + 9151.

It is an arithmetic number, because the mean of its divisors is an integer number (2866500).

Almost surely, 2^21250723 is an apocalyptic number.

21250723 is a deficient number, since it is larger than the sum of its proper divisors (1681277).

21250723 is a wasteful number, since it uses less digits than its factorization.

21250723 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3341.

The product of its (nonzero) digits is 840, while the sum is 22.

The square root of 21250723 is about 4609.8506483399. The cubic root of 21250723 is about 276.9860541142.

Adding to 21250723 its reverse (32705212), we get a palindrome (53955935).

The spelling of 21250723 in words is "twenty-one million, two hundred fifty thousand, seven hundred twenty-three".