21645460157 has 2 divisors, whose sum is σ = 21645460158. Its totient is φ = 21645460156.

The previous prime is 21645460153. The next prime is 21645460211. The reversal of 21645460157 is 75106454612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18056371876 + 3589088281 = 134374^2 + 59909^2 .

It is a cyclic number.

It is not a de Polignac number, because 21645460157 - 2² = 21645460153 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21645460153) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10822730078 + 10822730079.

It is an arithmetic number, because the mean of its divisors is an integer number (10822730079).

Almost surely, 2^21645460157 is an apocalyptic number.

It is an amenable number.

21645460157 is a deficient number, since it is larger than the sum of its proper divisors (1).

21645460157 is an equidigital number, since it uses as much as digits as its factorization.

21645460157 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 201600, while the sum is 41.

The spelling of 21645460157 in words is "twenty-one billion, six hundred forty-five million, four hundred sixty thousand, one hundred fifty-seven".