55497781 has 16 divisors (see below), whose sum is σ = 60208128. Its totient is φ = 51004800.

The previous prime is 55497763. The next prime is 55497811. The reversal of 55497781 is 18779455.

It is a happy number.

It is not a de Polignac number, because 55497781 - 2⁵ = 55497749 is a prime.

It is a super-2 number, since 2×55497781² = 6160007391847922, 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 (55491781) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 197361 + ... + 197641.

It is an arithmetic number, because the mean of its divisors is an integer number (3763008).

Almost surely, 2^55497781 is an apocalyptic number.

It is an amenable number.

55497781 is a deficient number, since it is larger than the sum of its proper divisors (4710347).

55497781 is a wasteful number, since it uses less digits than its factorization.

55497781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 612.

The product of its digits is 352800, while the sum is 46.

The square root of 55497781 is about 7449.6832818584. The cubic root of 55497781 is about 381.4390975934.

The spelling of 55497781 in words is "fifty-five million, four hundred ninety-seven thousand, seven hundred eighty-one".