21575406516 has 24 divisors (see below), whose sum is σ = 50351357280. Its totient is φ = 7190553312.

The previous prime is 21575406511. The next prime is 21575406539. The reversal of 21575406516 is 61560457512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21575406511) 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, 82746 + ... + 223601.

It is an arithmetic number, because the mean of its divisors is an integer number (2097973220).

Almost surely, 2^21575406516 is an apocalyptic number.

It is an amenable number.

21575406516 is an abundant number, since it is smaller than the sum of its proper divisors (28775950764).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21575406516 is a wasteful number, since it uses less digits than its factorization.

21575406516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 312223 (or 312221 counting only the distinct ones).

The product of its (nonzero) digits is 252000, while the sum is 42.

The spelling of 21575406516 in words is "twenty-one billion, five hundred seventy-five million, four hundred six thousand, five hundred sixteen".