21670784100 has 243 divisors, whose sum is σ = 79128686091. Its totient is φ = 4946256000.

The previous prime is 21670784087. The next prime is 21670784137. The reversal of 21670784100 is 148707612.

The square root of 21670784100 is 147210.

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

It can be written as a sum of positive squares in 4 ways, for example, as 1470415716 + 20200368384 = 38346^2 + 142128^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 30913750 + ... + 30914450.

Almost surely, 2^21670784100 is an apocalyptic number.

21670784100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

21670784100 is the 147210-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21670784100

21670784100 is an abundant number, since it is smaller than the sum of its proper divisors (57457901991).

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

21670784100 is a wasteful number, since it uses less digits than its factorization.

21670784100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1436 (or 718 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 36.

Multiplying 21670784100 by its sum of digits (36), we get a square (780148227600 = 883260²).

21670784100 divided by its sum of digits (36) gives a square (601966225 = 24535²).

The spelling of 21670784100 in words is "twenty-one billion, six hundred seventy million, seven hundred eighty-four thousand, one hundred".