42977821 has 2 divisors, whose sum is σ = 42977822. Its totient is φ = 42977820.

The previous prime is 42977813. The next prime is 42977839. The reversal of 42977821 is 12877924.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 41100921 + 1876900 = 6411^2 + 1370^2 .

It is a cyclic number.

It is not a de Polignac number, because 42977821 - 2³ = 42977813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42977021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21488910 + 21488911.

It is an arithmetic number, because the mean of its divisors is an integer number (21488911).

Almost surely, 2^42977821 is an apocalyptic number.

It is an amenable number.

42977821 is a deficient number, since it is larger than the sum of its proper divisors (1).

42977821 is an equidigital number, since it uses as much as digits as its factorization.

42977821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 56448, while the sum is 40.

The square root of 42977821 is about 6555.7471732824. The cubic root of 42977821 is about 350.2795616753.

The spelling of 42977821 in words is "forty-two million, nine hundred seventy-seven thousand, eight hundred twenty-one".