20720064 has 56 divisors (see below), whose sum is σ = 55156608. Its totient is φ = 6864640.

The previous prime is 20720057. The next prime is 20720083. The reversal of 20720064 is 46002702.

20720064 = 87² + 88² + ... + 397².

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 20720064.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 59539 + ... + 59885.

Almost surely, 2^20720064 is an apocalyptic number.

20720064 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20720064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27578304).

20720064 is an abundant number, since it is smaller than the sum of its proper divisors (34436544).

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

20720064 is a wasteful number, since it uses less digits than its factorization.

20720064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 673 (or 663 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 21.

The square root of 20720064 is about 4551.9297006874. The cubic root of 20720064 is about 274.6610214485.

Adding to 20720064 its reverse (46002702), we get a palindrome (66722766).

The spelling of 20720064 in words is "twenty million, seven hundred twenty thousand, sixty-four".