155825378621 has 4 divisors (see below), whose sum is σ = 169991322144. Its totient is φ = 141659435100.

The previous prime is 155825378581. The next prime is 155825378633. The reversal of 155825378621 is 126873528551.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 155825378621 - 2²⁶ = 155758269757 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155825378641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7082971745 + ... + 7082971766.

It is an arithmetic number, because the mean of its divisors is an integer number (42497830536).

Almost surely, 2^155825378621 is an apocalyptic number.

155825378621 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

155825378621 is a deficient number, since it is larger than the sum of its proper divisors (14165943523).

155825378621 is a wasteful number, since it uses less digits than its factorization.

155825378621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14165943522.

The product of its digits is 4032000, while the sum is 53.

The spelling of 155825378621 in words is "one hundred fifty-five billion, eight hundred twenty-five million, three hundred seventy-eight thousand, six hundred twenty-one".