21411211525 has 12 divisors (see below), whose sum is σ = 28963530144. Its totient is φ = 15571790000.

The previous prime is 21411211513. The next prime is 21411211583. The reversal of 21411211525 is 52511211412.

It is not a de Polignac number, because 21411211525 - 2¹⁵ = 21411178757 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21411211525.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 38929201 + ... + 38929750.

It is an arithmetic number, because the mean of its divisors is an integer number (2413627512).

Almost surely, 2^21411211525 is an apocalyptic number.

21411211525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21411211525 is a deficient number, since it is larger than the sum of its proper divisors (7552318619).

21411211525 is a wasteful number, since it uses less digits than its factorization.

21411211525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77858972 (or 77858967 counting only the distinct ones).

The product of its digits is 800, while the sum is 25.

Adding to 21411211525 its reverse (52511211412), we get a palindrome (73922422937).

The spelling of 21411211525 in words is "twenty-one billion, four hundred eleven million, two hundred eleven thousand, five hundred twenty-five".