21541645550 has 24 divisors (see below), whose sum is σ = 40090558296. Its totient is φ = 8611691040.

The previous prime is 21541645547. The next prime is 21541645613. The reversal of 21541645550 is 5554614512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 35957 + ... + 210656.

It is an arithmetic number, because the mean of its divisors is an integer number (1670439929).

Almost surely, 2^21541645550 is an apocalyptic number.

21541645550 is a deficient number, since it is larger than the sum of its proper divisors (18548912746).

21541645550 is a wasteful number, since it uses less digits than its factorization.

21541645550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 248372 (or 248367 counting only the distinct ones).

The product of its (nonzero) digits is 120000, while the sum is 38.

The spelling of 21541645550 in words is "twenty-one billion, five hundred forty-one million, six hundred forty-five thousand, five hundred fifty".