21155542502 has 8 divisors (see below), whose sum is σ = 31856790456. Its totient is φ = 10536612352.

The previous prime is 21155542501. The next prime is 21155542519. The reversal of 21155542502 is 20524555112.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21155542501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20578808 + ... + 20579835.

It is an arithmetic number, because the mean of its divisors is an integer number (3982098807).

Almost surely, 2^21155542502 is an apocalyptic number.

21155542502 is a deficient number, since it is larger than the sum of its proper divisors (10701247954).

21155542502 is a wasteful number, since it uses less digits than its factorization.

21155542502 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41158902.

The product of its (nonzero) digits is 20000, while the sum is 32.

The spelling of 21155542502 in words is "twenty-one billion, one hundred fifty-five million, five hundred forty-two thousand, five hundred two".