21540652154 has 12 divisors (see below), whose sum is σ = 37586240154. Its totient is φ = 9231708024.

The previous prime is 21540652121. The next prime is 21540652261. The reversal of 21540652154 is 45125604512.

It can be written as a sum of positive squares in only one way, i.e., 11254027225 + 10286624929 = 106085^2 + 101423^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 109901189 + ... + 109901384.

Almost surely, 2^21540652154 is an apocalyptic number.

21540652154 is a deficient number, since it is larger than the sum of its proper divisors (16045588000).

21540652154 is a wasteful number, since it uses less digits than its factorization.

21540652154 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 219802589 (or 219802582 counting only the distinct ones).

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

The spelling of 21540652154 in words is "twenty-one billion, five hundred forty million, six hundred fifty-two thousand, one hundred fifty-four".