21097272001 has 9 divisors (see below), whose sum is σ = 22847019849. Its totient is φ = 19472661936.

The previous prime is 21097271941. The next prime is 21097272011. The reversal of 21097272001 is 10027279012.

It is a happy number.

The square root of 21097272001 is 145249.

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 3546321601 + 17550950400 = 59551^2 + 132480^2 .

It is not a de Polignac number, because 21097272001 - 2¹⁷ = 21097140929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21097272011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1882651 + ... + 1893823.

It is an arithmetic number, because the mean of its divisors is an integer number (2538557761).

Almost surely, 2^21097272001 is an apocalyptic number.

21097272001 is the 145249-th square number.

21097272001 is the 72625-th centered octagonal number.

It is an amenable number.

21097272001 is a deficient number, since it is larger than the sum of its proper divisors (1749747848).

21097272001 is an frugal number, since it uses more digits than its factorization.

21097272001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22372 (or 11186 counting only the distinct ones).

The product of its (nonzero) digits is 3528, while the sum is 31.

The spelling of 21097272001 in words is "twenty-one billion, ninety-seven million, two hundred seventy-two thousand, one".