21155002513634 has 16 divisors (see below), whose sum is σ = 34889853828096. Its totient is φ = 9540194403600.

The previous prime is 21155002513633. The next prime is 21155002513663. The reversal of 21155002513634 is 43631520055112.

It is not an unprimeable number, because it can be changed into a prime (21155002513633) 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, 3785788637 + ... + 3785794224.

It is an arithmetic number, because the mean of its divisors is an integer number (2180615864256).

Almost surely, 2^{21155002513634} is an apocalyptic number.

21155002513634 is a deficient number, since it is larger than the sum of its proper divisors (13734851314462).

21155002513634 is a wasteful number, since it uses less digits than its factorization.

21155002513634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7571583001.

The product of its (nonzero) digits is 108000, while the sum is 38.

Adding to 21155002513634 its reverse (43631520055112), we get a palindrome (64786522568746).

The spelling of 21155002513634 in words is "twenty-one trillion, one hundred fifty-five billion, two million, five hundred thirteen thousand, six hundred thirty-four".