21073761 has 12 divisors (see below), whose sum is σ = 32230692. Its totient is φ = 13222656.

The previous prime is 21073739. The next prime is 21073799. The reversal of 21073761 is 16737012.

It can be written as a sum of positive squares in 2 ways, for example, as 11189025 + 9884736 = 3345^2 + 3144^2 .

It is not a de Polignac number, because 21073761 - 2²¹ = 18976609 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21073721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 68716 + ... + 69021.

It is an arithmetic number, because the mean of its divisors is an integer number (2685891).

Almost surely, 2^21073761 is an apocalyptic number.

It is an amenable number.

21073761 is a deficient number, since it is larger than the sum of its proper divisors (11156931).

21073761 is a wasteful number, since it uses less digits than its factorization.

21073761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137760 (or 137757 counting only the distinct ones).

The product of its (nonzero) digits is 1764, while the sum is 27.

The square root of 21073761 is about 4590.6166252476. The cubic root of 21073761 is about 276.2150576526.

The spelling of 21073761 in words is "twenty-one million, seventy-three thousand, seven hundred sixty-one".