21210999971 has 8 divisors (see below), whose sum is σ = 24638539104. Its totient is φ = 17882809920.

The previous prime is 21210999917. The next prime is 21210999973. The reversal of 21210999971 is 17999901212.

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

It is a cyclic number.

It is not a de Polignac number, because 21210999971 - 2¹⁸ = 21210737827 is a prime.

It is a super-3 number, since 3×21210999971³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21210999973) 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, 24836810 + ... + 24837663.

It is an arithmetic number, because the mean of its divisors is an integer number (3079817388).

Almost surely, 2^21210999971 is an apocalyptic number.

21210999971 is a deficient number, since it is larger than the sum of its proper divisors (3427539133).

21210999971 is an equidigital number, since it uses as much as digits as its factorization.

21210999971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49674541.

The product of its (nonzero) digits is 183708, while the sum is 50.

The spelling of 21210999971 in words is "twenty-one billion, two hundred ten million, nine hundred ninety-nine thousand, nine hundred seventy-one".