42634721 has 4 divisors (see below), whose sum is σ = 42741444. Its totient is φ = 42528000.

The previous prime is 42634717. The next prime is 42634729. The reversal of 42634721 is 12743624.

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 20205025 + 22429696 = 4495^2 + 4736^2 .

It is a cyclic number.

It is not a de Polignac number, because 42634721 - 2² = 42634717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (42634729) 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, 52760 + ... + 53561.

It is an arithmetic number, because the mean of its divisors is an integer number (10685361).

Almost surely, 2^42634721 is an apocalyptic number.

It is an amenable number.

42634721 is a deficient number, since it is larger than the sum of its proper divisors (106723).

42634721 is a wasteful number, since it uses less digits than its factorization.

42634721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106722.

The product of its digits is 8064, while the sum is 29.

The square root of 42634721 is about 6529.5268588160. The cubic root of 42634721 is about 349.3449544003.

The spelling of 42634721 in words is "forty-two million, six hundred thirty-four thousand, seven hundred twenty-one".