15005540001221 has 12 divisors (see below), whose sum is σ = 19042280818560. Its totient is φ = 11692628571960.

The previous prime is 15005540001209. The next prime is 15005540001233. The reversal of 15005540001221 is 12210004550051.

It is an interprime number because it is at equal distance from previous prime (15005540001209) and next prime (15005540001233).

It is not a de Polignac number, because 15005540001221 - 2³⁸ = 14730662094277 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15005540001821) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13919795381 + ... + 13919796458.

It is an arithmetic number, because the mean of its divisors is an integer number (1586856734880).

Almost surely, 2^{15005540001221} is an apocalyptic number.

15005540001221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

15005540001221 is a deficient number, since it is larger than the sum of its proper divisors (4036740817339).

15005540001221 is a wasteful number, since it uses less digits than its factorization.

15005540001221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27839591864 (or 27839591857 counting only the distinct ones).

The product of its (nonzero) digits is 2000, while the sum is 26.

Adding to 15005540001221 its reverse (12210004550051), we get a palindrome (27215544551272).

The spelling of 15005540001221 in words is "fifteen trillion, five billion, five hundred forty million, one thousand, two hundred twenty-one".