42949981 has 4 divisors (see below), whose sum is σ = 43760412. Its totient is φ = 42139552.

The previous prime is 42949967. The next prime is 42949997. The reversal of 42949981 is 18994924.

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

It can be written as a sum of positive squares in 2 ways, for example, as 10562500 + 32387481 = 3250^2 + 5691^2 .

It is a cyclic number.

It is not a de Polignac number, because 42949981 - 2⁷ = 42949853 is a prime.

It is a super-2 number, since 2×42949981² = 3689401735800722, 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 (42949931) 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, 405136 + ... + 405241.

It is an arithmetic number, because the mean of its divisors is an integer number (10940103).

Almost surely, 2^42949981 is an apocalyptic number.

It is an amenable number.

42949981 is a deficient number, since it is larger than the sum of its proper divisors (810431).

42949981 is an equidigital number, since it uses as much as digits as its factorization.

42949981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 810430.

The product of its digits is 186624, while the sum is 46.

The square root of 42949981 is about 6553.6235015448. The cubic root of 42949981 is about 350.2039111096.

The spelling of 42949981 in words is "forty-two million, nine hundred forty-nine thousand, nine hundred eighty-one".