21315155520542 has 16 divisors (see below), whose sum is σ = 34432928364240. Its totient is φ = 9837548640192.

The previous prime is 21315155520541. The next prime is 21315155520601. The reversal of 21315155520542 is 24502555151312.

It is a self number, because there is not a number n which added to its sum of digits gives 21315155520542.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21315155520541) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7763783 + ... + 10144290.

It is an arithmetic number, because the mean of its divisors is an integer number (2152058022765).

Almost surely, 2^{21315155520542} is an apocalyptic number.

21315155520542 is a deficient number, since it is larger than the sum of its proper divisors (13117772843698).

21315155520542 is a wasteful number, since it uses less digits than its factorization.

21315155520542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17953867.

The product of its (nonzero) digits is 300000, while the sum is 41.

The spelling of 21315155520542 in words is "twenty-one trillion, three hundred fifteen billion, one hundred fifty-five million, five hundred twenty thousand, five hundred forty-two".