42992721 has 8 divisors (see below), whose sum is σ = 63692960. Its totient is φ = 28661796.

The previous prime is 42992683. The next prime is 42992731. The reversal of 42992721 is 12729924.

It is not a de Polignac number, because 42992721 - 2⁶ = 42992657 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (42992731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 796135 + ... + 796188.

It is an arithmetic number, because the mean of its divisors is an integer number (7961620).

Almost surely, 2^42992721 is an apocalyptic number.

It is an amenable number.

42992721 is a deficient number, since it is larger than the sum of its proper divisors (20700239).

42992721 is a wasteful number, since it uses less digits than its factorization.

42992721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1592332 (or 1592326 counting only the distinct ones).

The product of its digits is 18144, while the sum is 36.

The square root of 42992721 is about 6556.8834822650. The cubic root of 42992721 is about 350.3200365243.

The spelling of 42992721 in words is "forty-two million, nine hundred ninety-two thousand, seven hundred twenty-one".