21391790153 has 2 divisors, whose sum is σ = 21391790154. Its totient is φ = 21391790152.

The previous prime is 21391790117. The next prime is 21391790179. The reversal of 21391790153 is 35109719312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17295406144 + 4096384009 = 131512^2 + 64003^2 .

It is a cyclic number.

It is not a de Polignac number, because 21391790153 - 2⁸ = 21391789897 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21391790153.

It is not a weakly prime, because it can be changed into another prime (21391720153) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10695895076 + 10695895077.

It is an arithmetic number, because the mean of its divisors is an integer number (10695895077).

Almost surely, 2^21391790153 is an apocalyptic number.

It is an amenable number.

21391790153 is a deficient number, since it is larger than the sum of its proper divisors (1).

21391790153 is an equidigital number, since it uses as much as digits as its factorization.

21391790153 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 51030, while the sum is 41.

The spelling of 21391790153 in words is "twenty-one billion, three hundred ninety-one million, seven hundred ninety thousand, one hundred fifty-three".