21554135340820 has 24 divisors (see below), whose sum is σ = 45263943714528. Its totient is φ = 8621604708000.

The previous prime is 21554135340809. The next prime is 21554135340823. The reversal of 21554135340820 is 2804353145512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21554135340823) 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, 593575 + ... + 6592465.

It is an arithmetic number, because the mean of its divisors is an integer number (1885997654772).

Almost surely, 2^{21554135340820} is an apocalyptic number.

21554135340820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21554135340820 is an abundant number, since it is smaller than the sum of its proper divisors (23709808373708).

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

21554135340820 is a wasteful number, since it uses less digits than its factorization.

21554135340820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6178551 (or 6178549 counting only the distinct ones).

The product of its (nonzero) digits is 576000, while the sum is 43.

The spelling of 21554135340820 in words is "twenty-one trillion, five hundred fifty-four billion, one hundred thirty-five million, three hundred forty thousand, eight hundred twenty".