21545515500455 has 16 divisors (see below), whose sum is σ = 25983662769504. Its totient is φ = 17150502865920.

The previous prime is 21545515500409. The next prime is 21545515500493. The reversal of 21545515500455 is 55400551554512.

It is a de Polignac number, because none of the positive numbers 2^k-21545515500455 is a prime.

It is a Duffinian number.

It is a congruent number.

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, 6056189 + ... + 8931318.

It is an arithmetic number, because the mean of its divisors is an integer number (1623978923094).

Almost surely, 2^{21545515500455} is an apocalyptic number.

21545515500455 is a deficient number, since it is larger than the sum of its proper divisors (4438147269049).

21545515500455 is a wasteful number, since it uses less digits than its factorization.

21545515500455 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14988946.

The product of its (nonzero) digits is 2500000, while the sum is 47.

The spelling of 21545515500455 in words is "twenty-one trillion, five hundred forty-five billion, five hundred fifteen million, five hundred thousand, four hundred fifty-five".