20681520 has 160 divisors (see below), whose sum is σ = 70227648. Its totient is φ = 5013504.

The previous prime is 20681513. The next prime is 20681539. The reversal of 20681520 is 2518602.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 150892 + ... + 151028.

Almost surely, 2^20681520 is an apocalyptic number.

20681520 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 20681520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35113824).

20681520 is an abundant number, since it is smaller than the sum of its proper divisors (49546128).

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

20681520 is a wasteful number, since it uses less digits than its factorization.

20681520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 207 (or 201 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 20681520 is about 4547.6939210989. The cubic root of 20681520 is about 274.4906052173.

The spelling of 20681520 in words is "twenty million, six hundred eighty-one thousand, five hundred twenty".