1523135421 has 28 divisors (see below), whose sum is σ = 2295824640. Its totient is φ = 1010014920.

The previous prime is 1523135401. The next prime is 1523135441. The reversal of 1523135421 is 1245313251.

1523135421 is a `hidden beast` number, since 1 + 5 + 231 + 3 + 5 + 421 = 666.

It is an interprime number because it is at equal distance from previous prime (1523135401) and next prime (1523135441).

It is not a de Polignac number, because 1523135421 - 2¹⁷ = 1523004349 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 (1523135401) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 133770 + ... + 144708.

Almost surely, 2^1523135421 is an apocalyptic number.

It is an amenable number.

1523135421 is a deficient number, since it is larger than the sum of its proper divisors (772689219).

1523135421 is an equidigital number, since it uses as much as digits as its factorization.

1523135421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11148 (or 11133 counting only the distinct ones).

The product of its digits is 3600, while the sum is 27.

The square root of 1523135421 is about 39027.3675899362. The cubic root of 1523135421 is about 1150.5694523159.

Adding to 1523135421 its reverse (1245313251), we get a palindrome (2768448672).

The spelling of 1523135421 in words is "one billion, five hundred twenty-three million, one hundred thirty-five thousand, four hundred twenty-one".