21254245685 has 16 divisors (see below), whose sum is σ = 25640459712. Its totient is φ = 16913366400.

The previous prime is 21254245657. The next prime is 21254245687. The reversal of 21254245685 is 58654245212.

It is not a de Polignac number, because 21254245685 - 2²⁸ = 20985810229 is a prime.

It is a super-2 number, since 2×21254245685² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21254245687) 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, 811850 + ... + 837620.

It is an arithmetic number, because the mean of its divisors is an integer number (1602528732).

Almost surely, 2^21254245685 is an apocalyptic number.

It is an amenable number.

21254245685 is a deficient number, since it is larger than the sum of its proper divisors (4386214027).

21254245685 is a wasteful number, since it uses less digits than its factorization.

21254245685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26644.

The product of its digits is 768000, while the sum is 44.

The spelling of 21254245685 in words is "twenty-one billion, two hundred fifty-four million, two hundred forty-five thousand, six hundred eighty-five".