42697821 has 16 divisors (see below), whose sum is σ = 59607936. Its totient is φ = 27134976.

The previous prime is 42697813. The next prime is 42697843. The reversal of 42697821 is 12879624.

It is not a de Polignac number, because 42697821 - 2³ = 42697813 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 42697821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42697891) 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, 23481 + ... + 25233.

It is an arithmetic number, because the mean of its divisors is an integer number (3725496).

Almost surely, 2^42697821 is an apocalyptic number.

It is an amenable number.

42697821 is a deficient number, since it is larger than the sum of its proper divisors (16910115).

42697821 is a wasteful number, since it uses less digits than its factorization.

42697821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2132.

The product of its digits is 48384, while the sum is 39.

The square root of 42697821 is about 6534.3569691286. The cubic root of 42697821 is about 349.5172146306.

It can be divided in two parts, 4269 and 7821, that added together give a triangular number (12090 = T₁₅₅).

The spelling of 42697821 in words is "forty-two million, six hundred ninety-seven thousand, eight hundred twenty-one".