21989249251 has 8 divisors (see below), whose sum is σ = 22829791104. Its totient is φ = 21156908160.

The previous prime is 21989249231. The next prime is 21989249257. The reversal of 21989249251 is 15294298912.

It is a happy number.

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 21989249251 - 2¹⁹ = 21988724963 is a prime.

It is a super-2 number, since 2×21989249251² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21989249257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2044726 + ... + 2055451.

It is an arithmetic number, because the mean of its divisors is an integer number (2853723888).

Almost surely, 2^21989249251 is an apocalyptic number.

21989249251 is a deficient number, since it is larger than the sum of its proper divisors (840541853).

21989249251 is a wasteful number, since it uses less digits than its factorization.

21989249251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4100381.

The product of its digits is 933120, while the sum is 52.

The spelling of 21989249251 in words is "twenty-one billion, nine hundred eighty-nine million, two hundred forty-nine thousand, two hundred fifty-one".