21000770021 has 16 divisors (see below), whose sum is σ = 27722943360. Its totient is φ = 15401633280.

The previous prime is 21000770017. The next prime is 21000770029. The reversal of 21000770021 is 12007700012.

It is not a de Polignac number, because 21000770021 - 2² = 21000770017 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21000769975 and 21000770002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000770029) 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, 8020376 + ... + 8022993.

It is an arithmetic number, because the mean of its divisors is an integer number (1732683960).

Almost surely, 2^21000770021 is an apocalyptic number.

It is an amenable number.

21000770021 is a deficient number, since it is larger than the sum of its proper divisors (6722173339).

21000770021 is a wasteful number, since it uses less digits than its factorization.

21000770021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16043404.

The product of its (nonzero) digits is 196, while the sum is 20.

The spelling of 21000770021 in words is "twenty-one billion, seven hundred seventy thousand, twenty-one".