21001606722 has 32 divisors (see below), whose sum is σ = 46689183360. Its totient is φ = 6997693680.

The previous prime is 21001606721. The next prime is 21001606723. The reversal of 21001606722 is 22760610012.

It is an interprime number because it is at equal distance from previous prime (21001606721) and next prime (21001606723).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21001606721) 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, 57472 + ... + 212852.

It is an arithmetic number, because the mean of its divisors is an integer number (1459036980).

Almost surely, 2^21001606722 is an apocalyptic number.

21001606722 is an abundant number, since it is smaller than the sum of its proper divisors (25687576638).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21001606722 is a wasteful number, since it uses less digits than its factorization.

21001606722 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157895 (or 157889 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The spelling of 21001606722 in words is "twenty-one billion, one million, six hundred six thousand, seven hundred twenty-two".