21556497534 has 32 divisors (see below), whose sum is σ = 50650233984. Its totient is φ = 6029789280.

The previous prime is 21556497463. The next prime is 21556497541. The reversal of 21556497534 is 43579465512.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12561204 + ... + 12562919.

It is an arithmetic number, because the mean of its divisors is an integer number (1582819812).

Almost surely, 2^21556497534 is an apocalyptic number.

21556497534 is an abundant number, since it is smaller than the sum of its proper divisors (29093736450).

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

21556497534 is a wasteful number, since it uses less digits than its factorization.

21556497534 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25124152.

The product of its digits is 4536000, while the sum is 51.

The spelling of 21556497534 in words is "twenty-one billion, five hundred fifty-six million, four hundred ninety-seven thousand, five hundred thirty-four".