21261022420153 has 2 divisors, whose sum is σ = 21261022420154. Its totient is φ = 21261022420152.

The previous prime is 21261022420139. The next prime is 21261022420193. The reversal of 21261022420153 is 35102422016212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17985164955664 + 3275857464489 = 4240892^2 + 1809933^2 .

It is a cyclic number.

It is not a de Polignac number, because 21261022420153 - 2¹³ = 21261022411961 is a prime.

It is not a weakly prime, because it can be changed into another prime (21261022420193) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10630511210076 + 10630511210077.

It is an arithmetic number, because the mean of its divisors is an integer number (10630511210077).

Almost surely, 2^{21261022420153} is an apocalyptic number.

It is an amenable number.

21261022420153 is a deficient number, since it is larger than the sum of its proper divisors (1).

21261022420153 is an equidigital number, since it uses as much as digits as its factorization.

21261022420153 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11520, while the sum is 31.

Adding to 21261022420153 its reverse (35102422016212), we get a palindrome (56363444436365).

The spelling of 21261022420153 in words is "twenty-one trillion, two hundred sixty-one billion, twenty-two million, four hundred twenty thousand, one hundred fifty-three".