21890031011 has 4 divisors (see below), whose sum is σ = 23177679912. Its totient is φ = 20602382112.

The previous prime is 21890030999. The next prime is 21890031067. The reversal of 21890031011 is 11013009812.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21890031011 - 2⁶ = 21890030947 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21890031211) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 643824425 + ... + 643824458.

It is an arithmetic number, because the mean of its divisors is an integer number (5794419978).

Almost surely, 2^21890031011 is an apocalyptic number.

21890031011 is a deficient number, since it is larger than the sum of its proper divisors (1287648901).

21890031011 is a wasteful number, since it uses less digits than its factorization.

21890031011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1287648900.

The product of its (nonzero) digits is 432, while the sum is 26.

The spelling of 21890031011 in words is "twenty-one billion, eight hundred ninety million, thirty-one thousand, eleven".