4991781 has 8 divisors (see below), whose sum is σ = 6835744. Its totient is φ = 3237840.

The previous prime is 4991771. The next prime is 4991801. The reversal of 4991781 is 1871994.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 4991781 - 2⁷ = 4991653 is a prime.

It is a super-2 number, since 2×4991781² = 49835755103922, 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 (4991771) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22375 + ... + 22596.

It is an arithmetic number, because the mean of its divisors is an integer number (854468).

Almost surely, 2^4991781 is an apocalyptic number.

It is an amenable number.

4991781 is a deficient number, since it is larger than the sum of its proper divisors (1843963).

4991781 is a wasteful number, since it uses less digits than its factorization.

4991781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45011.

The product of its digits is 18144, while the sum is 39.

The square root of 4991781 is about 2234.2293973538. The cubic root of 4991781 is about 170.9038479999.

The spelling of 4991781 in words is "four million, nine hundred ninety-one thousand, seven hundred eighty-one".