21001535144025 has 24 divisors (see below), whose sum is σ = 35066325623424. Its totient is φ = 11089919544000.

The previous prime is 21001535144017. The next prime is 21001535144033. The reversal of 21001535144025 is 52044153510012.

It is an interprime number because it is at equal distance from previous prime (21001535144017) and next prime (21001535144033).

It is not a de Polignac number, because 21001535144025 - 2³ = 21001535144017 is a prime.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 1386232369 + ... + 1386247518.

It is an arithmetic number, because the mean of its divisors is an integer number (1461096900976).

Almost surely, 2^{21001535144025} is an apocalyptic number.

21001535144025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21001535144025 is a deficient number, since it is larger than the sum of its proper divisors (14064790479399).

21001535144025 is a wasteful number, since it uses less digits than its factorization.

21001535144025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2772480001 (or 2772479996 counting only the distinct ones).

The product of its (nonzero) digits is 24000, while the sum is 33.

Adding to 21001535144025 its reverse (52044153510012), we get a palindrome (73045688654037).

The spelling of 21001535144025 in words is "twenty-one trillion, one billion, five hundred thirty-five million, one hundred forty-four thousand, twenty-five".