42121906 has 4 divisors (see below), whose sum is σ = 63182862. Its totient is φ = 21060952.

The previous prime is 42121889. The next prime is 42121913. The reversal of 42121906 is 60912124.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 41718681 + 403225 = 6459^2 + 635^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10530475 + ... + 10530478.

Almost surely, 2^42121906 is an apocalyptic number.

42121906 is a deficient number, since it is larger than the sum of its proper divisors (21060956).

42121906 is a wasteful number, since it uses less digits than its factorization.

42121906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21060955.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 42121906 is about 6490.1391356426. The cubic root of 42121906 is about 347.9386479680.

The spelling of 42121906 in words is "forty-two million, one hundred twenty-one thousand, nine hundred six".