21211999971 has 8 divisors (see below), whose sum is σ = 28469969664. Its totient is φ = 14047681800.

The previous prime is 21211999967. The next prime is 21211999979. The reversal of 21211999971 is 17999911212.

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

It is not a de Polignac number, because 21211999971 - 2² = 21211999967 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21211999979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23412351 + ... + 23413256.

It is an arithmetic number, because the mean of its divisors is an integer number (3558746208).

Almost surely, 2^21211999971 is an apocalyptic number.

21211999971 is a deficient number, since it is larger than the sum of its proper divisors (7257969693).

21211999971 is a wasteful number, since it uses less digits than its factorization.

21211999971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46825761.

The product of its digits is 183708, while the sum is 51.

The spelling of 21211999971 in words is "twenty-one billion, two hundred eleven million, nine hundred ninety-nine thousand, nine hundred seventy-one".