21653475685 has 16 divisors (see below), whose sum is σ = 27867836160. Its totient is φ = 16101408960.

The previous prime is 21653475661. The next prime is 21653475689. The reversal of 21653475685 is 58657435612.

It is not a de Polignac number, because 21653475685 - 2¹⁵ = 21653442917 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21653475689) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2145261 + ... + 2155330.

It is an arithmetic number, because the mean of its divisors is an integer number (1741739760).

Almost surely, 2^21653475685 is an apocalyptic number.

It is an amenable number.

21653475685 is a deficient number, since it is larger than the sum of its proper divisors (6214360475).

21653475685 is a wasteful number, since it uses less digits than its factorization.

21653475685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4300668.

The product of its digits is 6048000, while the sum is 52.

The spelling of 21653475685 in words is "twenty-one billion, six hundred fifty-three million, four hundred seventy-five thousand, six hundred eighty-five".