21270723 has 16 divisors (see below), whose sum is σ = 30198816. Its totient is φ = 13271040.

The previous prime is 21270719. The next prime is 21270751. The reversal of 21270723 is 32707212.

It is not a de Polignac number, because 21270723 - 2² = 21270719 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 = 21270693 and 21270702.

It is not an unprimeable number, because it can be changed into a prime (21270713) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8763 + ... + 10923.

It is an arithmetic number, because the mean of its divisors is an integer number (1887426).

Almost surely, 2^21270723 is an apocalyptic number.

21270723 is a deficient number, since it is larger than the sum of its proper divisors (8928093).

21270723 is a wasteful number, since it uses less digits than its factorization.

21270723 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2374.

The product of its (nonzero) digits is 1176, while the sum is 24.

The square root of 21270723 is about 4612.0194058568. The cubic root of 21270723 is about 277.0729214974.

Adding to 21270723 its reverse (32707212), we get a palindrome (53977935).

The spelling of 21270723 in words is "twenty-one million, two hundred seventy thousand, seven hundred twenty-three".