21501023740505 has 16 divisors (see below), whose sum is σ = 26240638184640. Its totient is φ = 16907925878592.

The previous prime is 21501023740459. The next prime is 21501023740513. The reversal of 21501023740505 is 50504732010512.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21501023740505 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 781082 + ... + 6603948.

It is an arithmetic number, because the mean of its divisors is an integer number (1640039886540).

Almost surely, 2^{21501023740505} is an apocalyptic number.

It is an amenable number.

21501023740505 is a deficient number, since it is larger than the sum of its proper divisors (4739614444135).

21501023740505 is a wasteful number, since it uses less digits than its factorization.

21501023740505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5835448.

The product of its (nonzero) digits is 42000, while the sum is 35.

The spelling of 21501023740505 in words is "twenty-one trillion, five hundred one billion, twenty-three million, seven hundred forty thousand, five hundred five".