20721060 has 36 divisors (see below), whose sum is σ = 62854428. Its totient is φ = 5525568.

The previous prime is 20721053. The next prime is 20721083. The reversal of 20721060 is 6012702.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 15872256 + 4848804 = 3984^2 + 2202^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 57379 + ... + 57738.

Almost surely, 2^20721060 is an apocalyptic number.

20721060 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20721060 is an abundant number, since it is smaller than the sum of its proper divisors (42133368).

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

20721060 is a wasteful number, since it uses less digits than its factorization.

20721060 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115132 (or 115127 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 20721060 is about 4552.0391035227. The cubic root of 20721060 is about 274.6654223035.

Adding to 20721060 its reverse (6012702), we get a palindrome (26733762).

The spelling of 20721060 in words is "twenty million, seven hundred twenty-one thousand, sixty".