21202272100 has 27 divisors (see below), whose sum is σ = 46012090411. Its totient is φ = 8480326400.

The previous prime is 21202272073. The next prime is 21202272101. The reversal of 21202272100 is 127220212.

The square root of 21202272100 is 145610.

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 1979004196 + 19223267904 = 44486^2 + 138648^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21202272101) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1448820 + ... + 1463380.

Almost surely, 2^21202272100 is an apocalyptic number.

21202272100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

21202272100 is the 145610-th square number.

It is an amenable number.

21202272100 is an abundant number, since it is smaller than the sum of its proper divisors (24809818311).

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

21202272100 is an frugal number, since it uses more digits than its factorization.

21202272100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29136 (or 14568 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 19.

Adding to 21202272100 its reverse (127220212), we get a palindrome (21329492312).

The spelling of 21202272100 in words is "twenty-one billion, two hundred two million, two hundred seventy-two thousand, one hundred".