21001542253415 has 16 divisors (see below), whose sum is σ = 25524300765600. Its totient is φ = 16587220387200.

The previous prime is 21001542253381. The next prime is 21001542253459. The reversal of 21001542253415 is 51435224510012.

It is not a de Polignac number, because 21001542253415 - 2¹⁰ = 21001542252391 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 59404289 + ... + 59756778.

It is an arithmetic number, because the mean of its divisors is an integer number (1595268797850).

Almost surely, 2^{21001542253415} is an apocalyptic number.

21001542253415 is a deficient number, since it is larger than the sum of its proper divisors (4522758512185).

21001542253415 is a wasteful number, since it uses less digits than its factorization.

21001542253415 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 119161522.

The product of its (nonzero) digits is 48000, while the sum is 35.

Adding to 21001542253415 its reverse (51435224510012), we get a palindrome (72436766763427).

The spelling of 21001542253415 in words is "twenty-one trillion, one billion, five hundred forty-two million, two hundred fifty-three thousand, four hundred fifteen".