20487720 has 192 divisors, whose sum is σ = 72394560. Its totient is φ = 4618240.

The previous prime is 20487713. The next prime is 20487721. The reversal of 20487720 is 2778402.

20487720 = 350² + 351² + ... + 470².

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20487721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 246799 + ... + 246881.

It is an arithmetic number, because the mean of its divisors is an integer number (377055).

Almost surely, 2^20487720 is an apocalyptic number.

20487720 is a gapful number since it is divisible by the number (20) 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 20487720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36197280).

20487720 is an abundant number, since it is smaller than the sum of its proper divisors (51906840).

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

20487720 is a wasteful number, since it uses less digits than its factorization.

20487720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136 (or 121 counting only the distinct ones).

The product of its (nonzero) digits is 6272, while the sum is 30.

The square root of 20487720 is about 4526.3362667835. The cubic root of 20487720 is about 273.6305247910.

The spelling of 20487720 in words is "twenty million, four hundred eighty-seven thousand, seven hundred twenty".