20551723 has 4 divisors (see below), whose sum is σ = 20562928. Its totient is φ = 20540520.

The previous prime is 20551703. The next prime is 20551733. The reversal of 20551723 is 32715502.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 32715502 = 2 ⋅16357751.

It is a cyclic number.

It is not a de Polignac number, because 20551723 - 2¹⁷ = 20420651 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20551703) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2136 + ... + 6757.

It is an arithmetic number, because the mean of its divisors is an integer number (5140732).

Almost surely, 2^20551723 is an apocalyptic number.

20551723 is a deficient number, since it is larger than the sum of its proper divisors (11205).

20551723 is an equidigital number, since it uses as much as digits as its factorization.

20551723 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11204.

The product of its (nonzero) digits is 2100, while the sum is 25.

The square root of 20551723 is about 4533.4008205761. The cubic root of 20551723 is about 273.9151663420.

The spelling of 20551723 in words is "twenty million, five hundred fifty-one thousand, seven hundred twenty-three".