20721619700 has 18 divisors (see below), whose sum is σ = 44965914966. Its totient is φ = 8288647840.

The previous prime is 20721619691. The next prime is 20721619799. The reversal of 20721619700 is 791612702.

It can be written as a sum of positive squares in 3 ways, for example, as 2065884304 + 18655735396 = 45452^2 + 136586^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 103607999 + ... + 103608198.

It is an arithmetic number, because the mean of its divisors is an integer number (2498106387).

Almost surely, 2^20721619700 is an apocalyptic number.

20721619700 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20721619700 is an abundant number, since it is smaller than the sum of its proper divisors (24244295266).

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

20721619700 is a wasteful number, since it uses less digits than its factorization.

20721619700 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 207216211 (or 207216204 counting only the distinct ones).

The product of its (nonzero) digits is 10584, while the sum is 35.

The spelling of 20721619700 in words is "twenty billion, seven hundred twenty-one million, six hundred nineteen thousand, seven hundred".