20721402889 has 8 divisors (see below), whose sum is σ = 22610560320. Its totient is φ = 18833144400.

The previous prime is 20721402853. The next prime is 20721402917. The reversal of 20721402889 is 98820412702.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20721402889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20721402089) 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, 176074 + ... + 269155.

It is an arithmetic number, because the mean of its divisors is an integer number (2826320040).

Almost surely, 2^20721402889 is an apocalyptic number.

It is an amenable number.

20721402889 is a deficient number, since it is larger than the sum of its proper divisors (1889157431).

20721402889 is a wasteful number, since it uses less digits than its factorization.

20721402889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 449471.

The product of its (nonzero) digits is 129024, while the sum is 43.

The spelling of 20721402889 in words is "twenty billion, seven hundred twenty-one million, four hundred two thousand, eight hundred eighty-nine".