21001132157 has 2 divisors, whose sum is σ = 21001132158. Its totient is φ = 21001132156.

The previous prime is 21001132049. The next prime is 21001132171. The reversal of 21001132157 is 75123110012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18237422116 + 2763710041 = 135046^2 + 52571^2 .

It is a cyclic number.

It is not a de Polignac number, because 21001132157 - 2⁸ = 21001131901 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21001132457) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500566078 + 10500566079.

It is an arithmetic number, because the mean of its divisors is an integer number (10500566079).

Almost surely, 2^21001132157 is an apocalyptic number.

It is an amenable number.

21001132157 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001132157 is an equidigital number, since it uses as much as digits as its factorization.

21001132157 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 420, while the sum is 23.

Adding to 21001132157 its reverse (75123110012), we get a palindrome (96124242169).

The spelling of 21001132157 in words is "twenty-one billion, one million, one hundred thirty-two thousand, one hundred fifty-seven".