21270180649 has 27 divisors (see below), whose sum is σ = 23683563813. Its totient is φ = 19097265792.

The previous prime is 21270180637. The next prime is 21270180689. The reversal of 21270180649 is 94608107212.

The square root of 21270180649 is 145843.

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 2352929049 + 18917251600 = 48507^2 + 137540^2 .

It is not a de Polignac number, because 21270180649 - 2²¹ = 21268083497 is a prime.

It is a super-2 number, since 2×21270180649² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21270180689) 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 26 ways as a sum of consecutive naturals, for example, 57024427 + ... + 57024799.

Almost surely, 2^21270180649 is an apocalyptic number.

21270180649 is the 145843-rd square number.

21270180649 is the 72922-nd centered octagonal number.

It is an amenable number.

21270180649 is a deficient number, since it is larger than the sum of its proper divisors (2413383164).

21270180649 is an frugal number, since it uses more digits than its factorization.

21270180649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 826 (or 413 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 40.

The spelling of 21270180649 in words is "twenty-one billion, two hundred seventy million, one hundred eighty thousand, six hundred forty-nine".