25155215421 has 16 divisors (see below), whose sum is σ = 38467213824. Its totient is φ = 14323612464.

The previous prime is 25155215417. The next prime is 25155215431. The reversal of 25155215421 is 12451255152.

It is not a de Polignac number, because 25155215421 - 2² = 25155215417 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25155215431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2110431 + ... + 2122316.

It is an arithmetic number, because the mean of its divisors is an integer number (2404200864).

Almost surely, 2^25155215421 is an apocalyptic number.

25155215421 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

25155215421 is a deficient number, since it is larger than the sum of its proper divisors (13311998403).

25155215421 is a wasteful number, since it uses less digits than its factorization.

25155215421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4233040.

The product of its digits is 20000, while the sum is 33.

The spelling of 25155215421 in words is "twenty-five billion, one hundred fifty-five million, two hundred fifteen thousand, four hundred twenty-one".