20721488 has 40 divisors (see below), whose sum is σ = 41319528. Its totient is φ = 10063872.

The previous prime is 20721479. The next prime is 20721497. The reversal of 20721488 is 88412702.

It is an interprime number because it is at equal distance from previous prime (20721479) and next prime (20721497).

It can be written as a sum of positive squares in 4 ways, for example, as 784 + 20720704 = 28^2 + 4552^2 .

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, 131906 + ... + 132062.

Almost surely, 2^20721488 is an apocalyptic number.

It is an amenable number.

20721488 is a deficient number, since it is larger than the sum of its proper divisors (20598040).

20721488 is a wasteful number, since it uses less digits than its factorization.

20721488 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 351 (or 345 counting only the distinct ones).

The product of its (nonzero) digits is 7168, while the sum is 32.

The square root of 20721488 is about 4552.0861151784. The cubic root of 20721488 is about 274.6673133907.

The spelling of 20721488 in words is "twenty million, seven hundred twenty-one thousand, four hundred eighty-eight".