126555021 has 16 divisors (see below), whose sum is σ = 198518400. Its totient is φ = 79406784.

The previous prime is 126555001. The next prime is 126555049. The reversal of 126555021 is 120555621.

126555021 is a `hidden beast` number, since 1 + 2 + 655 + 5 + 0 + 2 + 1 = 666.

It is not a de Polignac number, because 126555021 - 2⁹ = 126554509 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (126555001) 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, 137401 + ... + 138318.

It is an arithmetic number, because the mean of its divisors is an integer number (12407400).

Almost surely, 2^126555021 is an apocalyptic number.

It is an amenable number.

126555021 is a deficient number, since it is larger than the sum of its proper divisors (71963379).

126555021 is a wasteful number, since it uses less digits than its factorization.

126555021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 275745 (or 275739 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 27.

The square root of 126555021 is about 11249.6675950892. The cubic root of 126555021 is about 502.0648226107.

The spelling of 126555021 in words is "one hundred twenty-six million, five hundred fifty-five thousand, twenty-one".