1247557421 has 32 divisors (see below), whose sum is σ = 1453835520. Its totient is φ = 1059379200.

The previous prime is 1247557417. The next prime is 1247557457.

It is a happy number.

1247557421 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1247557421 - 2² = 1247557417 is a prime.

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1247557021) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3533981 + ... + 3534333.

It is an arithmetic number, because the mean of its divisors is an integer number (45432360).

Almost surely, 2^1247557421 is an apocalyptic number.

1247557421 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1247557421 is a deficient number, since it is larger than the sum of its proper divisors (206278099).

1247557421 is a wasteful number, since it uses less digits than its factorization.

1247557421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 677.

The product of its digits is 78400, while the sum is 38.

The square root of 1247557421 is about 35320.7788843904. The cubic root of 1247557421 is about 1076.5152372387.

It can be divided in two parts, 12475 and 57421, that added together give a palindrome (69896).

The spelling of 1247557421 in words is "one billion, two hundred forty-seven million, five hundred fifty-seven thousand, four hundred twenty-one".