21542620015 has 32 divisors (see below), whose sum is σ = 29849803776. Its totient is φ = 14619655680.

The previous prime is 21542620013. The next prime is 21542620063. The reversal of 21542620015 is 51002624512.

It is not a de Polignac number, because 21542620015 - 2¹ = 21542620013 is a prime.

It is a super-2 number, since 2×21542620015² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21542620013) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2934900 + ... + 2942230.

It is an arithmetic number, because the mean of its divisors is an integer number (932806368).

Almost surely, 2^21542620015 is an apocalyptic number.

21542620015 is a deficient number, since it is larger than the sum of its proper divisors (8307183761).

21542620015 is a wasteful number, since it uses less digits than its factorization.

21542620015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8199.

The product of its (nonzero) digits is 4800, while the sum is 28.

The spelling of 21542620015 in words is "twenty-one billion, five hundred forty-two million, six hundred twenty thousand, fifteen".