21020720722 has 16 divisors (see below), whose sum is σ = 31788748800. Its totient is φ = 10424520288.

The previous prime is 21020720689. The next prime is 21020720729. The reversal of 21020720722 is 22702702012.

It is not an unprimeable number, because it can be changed into a prime (21020720729) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1020279 + ... + 1040677.

It is an arithmetic number, because the mean of its divisors is an integer number (1986796800).

Almost surely, 2^21020720722 is an apocalyptic number.

21020720722 is a deficient number, since it is larger than the sum of its proper divisors (10768028078).

21020720722 is a wasteful number, since it uses less digits than its factorization.

21020720722 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24585.

The product of its (nonzero) digits is 1568, while the sum is 25.

The spelling of 21020720722 in words is "twenty-one billion, twenty million, seven hundred twenty thousand, seven hundred twenty-two".