21519800438 has 16 divisors (see below), whose sum is σ = 34185322944. Its totient is φ = 10124945280.

The previous prime is 21519800437. The next prime is 21519800443. The reversal of 21519800438 is 83400891512.

It is a junction number, because it is equal to n+sod(n) for n = 21519800395 and 21519800404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21519800437) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 117356 + ... + 238352.

It is an arithmetic number, because the mean of its divisors is an integer number (2136582684).

Almost surely, 2^21519800438 is an apocalyptic number.

21519800438 is a deficient number, since it is larger than the sum of its proper divisors (12665522506).

21519800438 is a wasteful number, since it uses less digits than its factorization.

21519800438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126247.

The product of its (nonzero) digits is 69120, while the sum is 41.

The spelling of 21519800438 in words is "twenty-one billion, five hundred nineteen million, eight hundred thousand, four hundred thirty-eight".