21198619525 has 6 divisors (see below), whose sum is σ = 26286288242. Its totient is φ = 16958895600.

The previous prime is 21198619511. The next prime is 21198619543. The reversal of 21198619525 is 52591689112.

It can be written as a sum of positive squares in 3 ways, for example, as 2176968964 + 19021650561 = 46658^2 + 137919^2 .

It is not a de Polignac number, because 21198619525 - 2¹⁵ = 21198586757 is a prime.

It is a super-2 number, since 2×21198619525² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 423972366 + ... + 423972415.

Almost surely, 2^21198619525 is an apocalyptic number.

21198619525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21198619525 is a deficient number, since it is larger than the sum of its proper divisors (5087668717).

21198619525 is an equidigital number, since it uses as much as digits as its factorization.

21198619525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 847944791 (or 847944786 counting only the distinct ones).

The product of its digits is 388800, while the sum is 49.

The spelling of 21198619525 in words is "twenty-one billion, one hundred ninety-eight million, six hundred nineteen thousand, five hundred twenty-five".