21603217762157 has 4 divisors (see below), whose sum is σ = 22873995277596. Its totient is φ = 20332440246720.

The previous prime is 21603217762151. The next prime is 21603217762183. The reversal of 21603217762157 is 75126771230612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 17025410906596 + 4577806855561 = 4126186^2 + 2139581^2 .

It is a cyclic number.

It is not a de Polignac number, because 21603217762157 - 2⁴ = 21603217762141 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21603217762151) 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, 635388757694 + ... + 635388757727.

It is an arithmetic number, because the mean of its divisors is an integer number (5718498819399).

Almost surely, 2^{21603217762157} is an apocalyptic number.

It is an amenable number.

21603217762157 is a deficient number, since it is larger than the sum of its proper divisors (1270777515439).

21603217762157 is a wasteful number, since it uses less digits than its factorization.

21603217762157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1270777515438.

The product of its (nonzero) digits is 1481760, while the sum is 50.

Adding to 21603217762157 its reverse (75126771230612), we get a palindrome (96729988992769).

The spelling of 21603217762157 in words is "twenty-one trillion, six hundred three billion, two hundred seventeen million, seven hundred sixty-two thousand, one hundred fifty-seven".