21542154051 has 24 divisors (see below), whose sum is σ = 31586476432. Its totient is φ = 13049625600.

The previous prime is 21542154047. The next prime is 21542154079. The reversal of 21542154051 is 15045124512.

It is not a de Polignac number, because 21542154051 - 2² = 21542154047 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21542154251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 814995 + ... + 841011.

Almost surely, 2^21542154051 is an apocalyptic number.

21542154051 is a deficient number, since it is larger than the sum of its proper divisors (10044322381).

21542154051 is a wasteful number, since it uses less digits than its factorization.

21542154051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28323 (or 28312 counting only the distinct ones).

The product of its (nonzero) digits is 8000, while the sum is 30.

Adding to 21542154051 its reverse (15045124512), we get a palindrome (36587278563).

The spelling of 21542154051 in words is "twenty-one billion, five hundred forty-two million, one hundred fifty-four thousand, fifty-one".