21087540938 has 16 divisors (see below), whose sum is σ = 33009871680. Its totient is φ = 10084341696.

The previous prime is 21087540937. The next prime is 21087540941. The reversal of 21087540938 is 83904578012.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21087540892 and 21087540901.

It is not an unprimeable number, because it can be changed into a prime (21087540937) 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, 671381 + ... + 702087.

It is an arithmetic number, because the mean of its divisors is an integer number (2063116980).

Almost surely, 2^21087540938 is an apocalyptic number.

21087540938 is a deficient number, since it is larger than the sum of its proper divisors (11922330742).

21087540938 is a wasteful number, since it uses less digits than its factorization.

21087540938 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45661.

The product of its (nonzero) digits is 483840, while the sum is 47.

The spelling of 21087540938 in words is "twenty-one billion, eighty-seven million, five hundred forty thousand, nine hundred thirty-eight".