21053555251 has 2 divisors, whose sum is σ = 21053555252. Its totient is φ = 21053555250.

The previous prime is 21053555219. The next prime is 21053555273. The reversal of 21053555251 is 15255535012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21053555251 - 2⁵ = 21053555219 is a prime.

It is a super-3 number, since 3×21053555251³ (a number of 32 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (21053555351) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10526777625 + 10526777626.

It is an arithmetic number, because the mean of its divisors is an integer number (10526777626).

Almost surely, 2^21053555251 is an apocalyptic number.

21053555251 is a deficient number, since it is larger than the sum of its proper divisors (1).

21053555251 is an equidigital number, since it uses as much as digits as its factorization.

21053555251 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 37500, while the sum is 34.

The spelling of 21053555251 in words is "twenty-one billion, fifty-three million, five hundred fifty-five thousand, two hundred fifty-one".