55978157 has 4 divisors (see below), whose sum is σ = 57783936. Its totient is φ = 54172380.

The previous prime is 55978061. The next prime is 55978163. The reversal of 55978157 is 75187955.

It is a happy number.

55978157 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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, and also an emirpimes, since its reverse is a distinct semiprime: 75187955 = 5 ⋅15037591.

It is a cyclic number.

It is not a de Polignac number, because 55978157 - 2¹⁰ = 55977133 is a prime.

It is a super-2 number, since 2×55978157² = 6267108122233298, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55908157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 902843 + ... + 902904.

It is an arithmetic number, because the mean of its divisors is an integer number (14445984).

Almost surely, 2^55978157 is an apocalyptic number.

It is an amenable number.

55978157 is a deficient number, since it is larger than the sum of its proper divisors (1805779).

55978157 is a wasteful number, since it uses less digits than its factorization.

55978157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1805778.

The product of its digits is 441000, while the sum is 47.

The square root of 55978157 is about 7481.8551843777. The cubic root of 55978157 is about 382.5364870429.

The spelling of 55978157 in words is "fifty-five million, nine hundred seventy-eight thousand, one hundred fifty-seven".