20724797440 has 104 divisors (see below), whose sum is σ = 49878275400. Its totient is φ = 8265793536.

The previous prime is 20724797413. The next prime is 20724797453. The reversal of 20724797440 is 4479742702.

It can be written as a sum of positive squares in 4 ways, for example, as 7834374144 + 12890423296 = 88512^2 + 113536^2 .

It is a super-4 number, since 4×20724797440⁴ (a number of 42 digits) contains 4444 as substring.

It is a hoax number, since the sum of its digits (46) coincides with the sum of the digits of its distinct prime factors.

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, 8129286 + ... + 8131834.

Almost surely, 2^20724797440 is an apocalyptic number.

20724797440 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 20724797440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24939137700).

20724797440 is an abundant number, since it is smaller than the sum of its proper divisors (29153477960).

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

20724797440 is an equidigital number, since it uses as much as digits as its factorization.

20724797440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2975 (or 2953 counting only the distinct ones).

The product of its (nonzero) digits is 790272, while the sum is 46.

The spelling of 20724797440 in words is "twenty billion, seven hundred twenty-four million, seven hundred ninety-seven thousand, four hundred forty".