21238919077 has 8 divisors (see below), whose sum is σ = 22491700056. Its totient is φ = 19986519552.

The previous prime is 21238919063. The next prime is 21238919123. The reversal of 21238919077 is 77091983212.

It can be written as a sum of positive squares in 4 ways, for example, as 14508481 + 21224410596 = 3809^2 + 145686^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21238919077 - 2⁷ = 21238918949 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21238919077.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21238919477) 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 7 ways as a sum of consecutive naturals, for example, 23523 + ... + 207439.

It is an arithmetic number, because the mean of its divisors is an integer number (2811462507).

Almost surely, 2^21238919077 is an apocalyptic number.

It is an amenable number.

21238919077 is a deficient number, since it is larger than the sum of its proper divisors (1252780979).

21238919077 is a wasteful number, since it uses less digits than its factorization.

21238919077 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 190727.

The product of its (nonzero) digits is 381024, while the sum is 49.

The spelling of 21238919077 in words is "twenty-one billion, two hundred thirty-eight million, nine hundred nineteen thousand, seventy-seven".