55781040 has 80 divisors (see below), whose sum is σ = 197630208. Its totient is φ = 12749568.

The previous prime is 55781009. The next prime is 55781071. The reversal of 55781040 is 4018755.

It is an interprime number because it is at equal distance from previous prime (55781009) and next prime (55781071).

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×55781040² = 6223048846963200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 55780989 and 55781007.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14922 + ... + 18281.

Almost surely, 2^55781040 is an apocalyptic number.

It is an amenable number.

55781040 is an abundant number, since it is smaller than the sum of its proper divisors (141849168).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

55781040 is a wasteful number, since it uses less digits than its factorization.

55781040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33226 (or 33220 counting only the distinct ones).

The product of its (nonzero) digits is 5600, while the sum is 30.

The square root of 55781040 is about 7468.6705644311. The cubic root of 55781040 is about 382.0869478534.

Adding to 55781040 its reverse (4018755), we get a palindrome (59799795).

The spelling of 55781040 in words is "fifty-five million, seven hundred eighty-one thousand, forty".