21072720842 has 8 divisors (see below), whose sum is σ = 32983389216. Its totient is φ = 10078257772.

The previous prime is 21072720833. The next prime is 21072720853. The reversal of 21072720842 is 24802727012.

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

It is a super-2 number, since 2×21072720842² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 229051268 + ... + 229051359.

It is an arithmetic number, because the mean of its divisors is an integer number (4122923652).

Almost surely, 2^21072720842 is an apocalyptic number.

21072720842 is a deficient number, since it is larger than the sum of its proper divisors (11910668374).

21072720842 is a wasteful number, since it uses less digits than its factorization.

21072720842 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 458102652.

The product of its (nonzero) digits is 25088, while the sum is 35.

The spelling of 21072720842 in words is "twenty-one billion, seventy-two million, seven hundred twenty thousand, eight hundred forty-two".