125078591821 has 2 divisors, whose sum is σ = 125078591822. Its totient is φ = 125078591820.

The previous prime is 125078591819. The next prime is 125078591837. The reversal of 125078591821 is 128195870521.

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., 87415426921 + 37663164900 = 295661^2 + 194070^2 .

It is a cyclic number.

It is not a de Polignac number, because 125078591821 - 2¹ = 125078591819 is a prime.

Together with 125078591819, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (125078594821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 62539295910 + 62539295911.

It is an arithmetic number, because the mean of its divisors is an integer number (62539295911).

Almost surely, 2^125078591821 is an apocalyptic number.

It is an amenable number.

125078591821 is a deficient number, since it is larger than the sum of its proper divisors (1).

125078591821 is an equidigital number, since it uses as much as digits as its factorization.

125078591821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 403200, while the sum is 49.

The spelling of 125078591821 in words is "one hundred twenty-five billion, seventy-eight million, five hundred ninety-one thousand, eight hundred twenty-one".