21046413761 has 4 divisors (see below), whose sum is σ = 21061655124. Its totient is φ = 21031172400.

The previous prime is 21046413719. The next prime is 21046413767. The reversal of 21046413761 is 16731464012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14970990736 + 6075423025 = 122356^2 + 77945^2 .

It is a cyclic number.

It is not a de Polignac number, because 21046413761 - 2⁶ = 21046413697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21046413767) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7618610 + ... + 7621371.

It is an arithmetic number, because the mean of its divisors is an integer number (5265413781).

Almost surely, 2^21046413761 is an apocalyptic number.

It is an amenable number.

21046413761 is a deficient number, since it is larger than the sum of its proper divisors (15241363).

21046413761 is a wasteful number, since it uses less digits than its factorization.

21046413761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15241362.

The product of its (nonzero) digits is 24192, while the sum is 35.

Adding to 21046413761 its reverse (16731464012), we get a palindrome (37777877773).

The spelling of 21046413761 in words is "twenty-one billion, forty-six million, four hundred thirteen thousand, seven hundred sixty-one".