1245665421 has 144 divisors (see below), whose sum is σ = 2507476608. Its totient is φ = 575424000.

The previous prime is 1245665401. The next prime is 1245665437.

1245665421 is a `hidden beast` number, since 1 + 24 + 566 + 54 + 21 = 666.

1245665421 is nontrivially palindromic in base 10.

1245665421 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 1245665421 - 2¹⁸ = 1245403277 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1245665401) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 12333271 + ... + 12333371.

It is an arithmetic number, because the mean of its divisors is an integer number (17413032).

Almost surely, 2^1245665421 is an apocalyptic number.

1245665421 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1245665421 is an abundant number, since it is smaller than the sum of its proper divisors (1261811187).

1245665421 is a wasteful number, since it uses less digits than its factorization.

1245665421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 212 (or 172 counting only the distinct ones).

The product of its digits is 57600, while the sum is 36.

The square root of 1245665421 is about 35293.9856207825. The cubic root of 1245665421 is about 1075.9707606769.

It can be divided in two parts, 12456 and 65421, that added together give a palindrome (77877).

The spelling of 1245665421 in words is "one billion, two hundred forty-five million, six hundred sixty-five thousand, four hundred twenty-one".