42721861 has 16 divisors (see below), whose sum is σ = 55350400. Its totient is φ = 32021568.

The previous prime is 42721859. The next prime is 42721873. The reversal of 42721861 is 16812724.

It is a cyclic number.

It is not a de Polignac number, because 42721861 - 2¹ = 42721859 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42721801) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10626 + ... + 14083.

It is an arithmetic number, because the mean of its divisors is an integer number (3459400).

Almost surely, 2^42721861 is an apocalyptic number.

It is an amenable number.

42721861 is a deficient number, since it is larger than the sum of its proper divisors (12628539).

42721861 is a wasteful number, since it uses less digits than its factorization.

42721861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24748.

The product of its digits is 5376, while the sum is 31.

The square root of 42721861 is about 6536.1962179849. The cubic root of 42721861 is about 349.5827981288.

The spelling of 42721861 in words is "forty-two million, seven hundred twenty-one thousand, eight hundred sixty-one".