21542453685 has 32 divisors (see below), whose sum is σ = 39188350080. Its totient is φ = 11222112384.

The previous prime is 21542453677. The next prime is 21542453731. The reversal of 21542453685 is 58635424512.

21542453685 is a `hidden beast` number, since 2 + 1 + 542 + 45 + 3 + 68 + 5 = 666.

It is not a de Polignac number, because 21542453685 - 2³ = 21542453677 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 21542453685.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1849704 + ... + 1861313.

It is an arithmetic number, because the mean of its divisors is an integer number (1224635940).

Almost surely, 2^21542453685 is an apocalyptic number.

It is an amenable number.

21542453685 is a deficient number, since it is larger than the sum of its proper divisors (17645896395).

21542453685 is a wasteful number, since it uses less digits than its factorization.

21542453685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3711074 (or 3711068 counting only the distinct ones).

The product of its digits is 1152000, while the sum is 45.

The spelling of 21542453685 in words is "twenty-one billion, five hundred forty-two million, four hundred fifty-three thousand, six hundred eighty-five".