21155001145 has 8 divisors (see below), whose sum is σ = 25864982856. Its totient is φ = 16604679936.

The previous prime is 21155001107. The next prime is 21155001151. The reversal of 21155001145 is 54110055112.

It can be written as a sum of positive squares in 4 ways, for example, as 61214976 + 21093786169 = 7824^2 + 145237^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21155001145 - 2¹⁵ = 21154968377 is a prime.

It is a super-2 number, since 2×21155001145² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 39914832 + ... + 39915361.

It is an arithmetic number, because the mean of its divisors is an integer number (3233122857).

Almost surely, 2^21155001145 is an apocalyptic number.

It is an amenable number.

21155001145 is a deficient number, since it is larger than the sum of its proper divisors (4709981711).

21155001145 is an equidigital number, since it uses as much as digits as its factorization.

21155001145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79830251.

The product of its (nonzero) digits is 1000, while the sum is 25.

Adding to 21155001145 its reverse (54110055112), we get a palindrome (75265056257).

The spelling of 21155001145 in words is "twenty-one billion, one hundred fifty-five million, one thousand, one hundred forty-five".