21072644945 has 16 divisors (see below), whose sum is σ = 27707548608. Its totient is φ = 15258037440.

The previous prime is 21072644927. The next prime is 21072644951. The reversal of 21072644945 is 54944627012.

It is not a de Polignac number, because 21072644945 - 2²⁰ = 21071596369 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21072644896 and 21072644905.

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, 831434 + ... + 856403.

It is an arithmetic number, because the mean of its divisors is an integer number (1731721788).

Almost surely, 2^21072644945 is an apocalyptic number.

It is an amenable number.

21072644945 is a deficient number, since it is larger than the sum of its proper divisors (6634903663).

21072644945 is a wasteful number, since it uses less digits than its factorization.

21072644945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1688080.

The product of its (nonzero) digits is 483840, while the sum is 44.

The spelling of 21072644945 in words is "twenty-one billion, seventy-two million, six hundred forty-four thousand, nine hundred forty-five".