42997821 has 8 divisors (see below), whose sum is σ = 57898464. Its totient is φ = 28381200.

The previous prime is 42997819. The next prime is 42997831. The reversal of 42997821 is 12879924.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 42997821 - 2¹ = 42997819 is a prime.

It is a super-2 number, since 2×42997821² = 3697625221496082, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42997831) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 70651 + ... + 71256.

It is an arithmetic number, because the mean of its divisors is an integer number (7237308).

Almost surely, 2^42997821 is an apocalyptic number.

It is an amenable number.

42997821 is a deficient number, since it is larger than the sum of its proper divisors (14900643).

42997821 is a wasteful number, since it uses less digits than its factorization.

42997821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142011.

The product of its digits is 72576, while the sum is 42.

The square root of 42997821 is about 6557.2723750047. The cubic root of 42997821 is about 350.3338881834. Note that the first 3 decimals are identical.

The spelling of 42997821 in words is "forty-two million, nine hundred ninety-seven thousand, eight hundred twenty-one".