21787890062500 has 63 divisors (see below), whose sum is σ = 47662952230621. Its totient is φ = 8714689250000.

The previous prime is 21787890062473. The next prime is 21787890062503. The reversal of 21787890062500 is 526009878712.

The square root of 21787890062500 is 4667750.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 3 ways, for example, as 19088283332196 + 2699606730304 = 4369014^2 + 1643048^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21787890062503) by changing a digit.

It is a polite number, since it can be written in 20 ways as a sum of consecutive naturals, for example, 1166928165 + ... + 1166946835.

Almost surely, 2^{21787890062500} is an apocalyptic number.

21787890062500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

21787890062500 is the 4667750-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21787890062500

21787890062500 is an abundant number, since it is smaller than the sum of its proper divisors (25875062168121).

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

21787890062500 is an frugal number, since it uses more digits than its factorization.

21787890062500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37376 (or 18678 counting only the distinct ones).

The product of its (nonzero) digits is 3386880, while the sum is 55.

The spelling of 21787890062500 in words is "twenty-one trillion, seven hundred eighty-seven billion, eight hundred ninety million, sixty-two thousand, five hundred".