21061723 has 8 divisors (see below), whose sum is σ = 21534336. Its totient is φ = 20592000.

The previous prime is 21061717. The next prime is 21061739. The reversal of 21061723 is 32716012.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21061723 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21061694 and 21061703.

It is not an unprimeable number, because it can be changed into a prime (21061783) 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, 20758 + ... + 21748.

It is an arithmetic number, because the mean of its divisors is an integer number (2691792).

Almost surely, 2^21061723 is an apocalyptic number.

21061723 is a deficient number, since it is larger than the sum of its proper divisors (472613).

21061723 is an equidigital number, since it uses as much as digits as its factorization.

21061723 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1445.

The product of its (nonzero) digits is 504, while the sum is 22.

The square root of 21061723 is about 4589.3052851167. The cubic root of 21061723 is about 276.1624533706.

Adding to 21061723 its reverse (32716012), we get a palindrome (53777735).

The spelling of 21061723 in words is "twenty-one million, sixty-one thousand, seven hundred twenty-three".