21201100957 has 2 divisors, whose sum is σ = 21201100958. Its totient is φ = 21201100956.

The previous prime is 21201100919. The next prime is 21201100967. The reversal of 21201100957 is 75900110212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18266603716 + 2934497241 = 135154^2 + 54171^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21201100957 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21201100967) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600550478 + 10600550479.

It is an arithmetic number, because the mean of its divisors is an integer number (10600550479).

Almost surely, 2^21201100957 is an apocalyptic number.

It is an amenable number.

21201100957 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201100957 is an equidigital number, since it uses as much as digits as its factorization.

21201100957 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1260, while the sum is 28.

The spelling of 21201100957 in words is "twenty-one billion, two hundred one million, one hundred thousand, nine hundred fifty-seven".