20723430 has 64 divisors (see below), whose sum is σ = 61221888. Its totient is φ = 4371840.

The previous prime is 20723419. The next prime is 20723431. The reversal of 20723430 is 3432702.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20723397 and 20723406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20723431) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1066 + ... + 6525.

It is an arithmetic number, because the mean of its divisors is an integer number (956592).

Almost surely, 2^20723430 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20723430, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30610944).

20723430 is an abundant number, since it is smaller than the sum of its proper divisors (40498458).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20723430 is a wasteful number, since it uses less digits than its factorization.

20723430 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7621.

The product of its (nonzero) digits is 1008, while the sum is 21.

The square root of 20723430 is about 4552.2994189750. The cubic root of 20723430 is about 274.6758936506.

The spelling of 20723430 in words is "twenty million, seven hundred twenty-three thousand, four hundred thirty".