55781563 has 4 divisors (see below), whose sum is σ = 56545768. Its totient is φ = 55017360.

The previous prime is 55781543. The next prime is 55781567. The reversal of 55781563 is 36518755.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55781563 is a prime.

It is a super-2 number, since 2×55781563² = 6223165541445938, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (55781567) 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, 381993 + ... + 382138.

It is an arithmetic number, because the mean of its divisors is an integer number (14136442).

Almost surely, 2^55781563 is an apocalyptic number.

55781563 is a deficient number, since it is larger than the sum of its proper divisors (764205).

55781563 is an equidigital number, since it uses as much as digits as its factorization.

55781563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 764204.

The product of its digits is 126000, while the sum is 40.

The square root of 55781563 is about 7468.7055772737. The cubic root of 55781563 is about 382.0881419918.

The spelling of 55781563 in words is "fifty-five million, seven hundred eighty-one thousand, five hundred sixty-three".