21616121656540 has 12 divisors (see below), whose sum is σ = 45393855478776. Its totient is φ = 8646448662608.

The previous prime is 21616121656531. The next prime is 21616121656603. The reversal of 21616121656540 is 4565612161612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 540403041394 + ... + 540403041433.

It is an arithmetic number, because the mean of its divisors is an integer number (3782821289898).

Almost surely, 2^{21616121656540} is an apocalyptic number.

21616121656540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21616121656540 is an abundant number, since it is smaller than the sum of its proper divisors (23777733822236).

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

21616121656540 is a wasteful number, since it uses less digits than its factorization.

21616121656540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1080806082836 (or 1080806082834 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 46.

The spelling of 21616121656540 in words is "twenty-one trillion, six hundred sixteen billion, one hundred twenty-one million, six hundred fifty-six thousand, five hundred forty".