21554202505 has 96 divisors (see below), whose sum is σ = 31568624640. Its totient is φ = 14050713600.

The previous prime is 21554202479. The next prime is 21554202511. The reversal of 21554202505 is 50520245512.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-21554202505 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 21361441 + ... + 21362449.

It is an arithmetic number, because the mean of its divisors is an integer number (328839840).

Almost surely, 2^21554202505 is an apocalyptic number.

It is an amenable number.

21554202505 is a deficient number, since it is larger than the sum of its proper divisors (10014422135).

21554202505 is a wasteful number, since it uses less digits than its factorization.

21554202505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1151 (or 1140 counting only the distinct ones).

The product of its (nonzero) digits is 20000, while the sum is 31.

The spelling of 21554202505 in words is "twenty-one billion, five hundred fifty-four million, two hundred two thousand, five hundred five".