21489949925 has 6 divisors (see below), whose sum is σ = 26647537938. Its totient is φ = 17191959920.

The previous prime is 21489949903. The next prime is 21489949933. The reversal of 21489949925 is 52994998412.

It can be written as a sum of positive squares in 3 ways, for example, as 411846436 + 21078103489 = 20294^2 + 145183^2 .

It is not a de Polignac number, because 21489949925 - 2⁶ = 21489949861 is a prime.

It is a super-3 number, since 3×21489949925³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 429798974 + ... + 429799023.

It is an arithmetic number, because the mean of its divisors is an integer number (4441256323).

Almost surely, 2^21489949925 is an apocalyptic number.

21489949925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21489949925 is a deficient number, since it is larger than the sum of its proper divisors (5157588013).

21489949925 is an equidigital number, since it uses as much as digits as its factorization.

21489949925 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 859598007 (or 859598002 counting only the distinct ones).

The product of its digits is 16796160, while the sum is 62.

The spelling of 21489949925 in words is "twenty-one billion, four hundred eighty-nine million, nine hundred forty-nine thousand, nine hundred twenty-five".