1521140021 has 2 divisors, whose sum is σ = 1521140022. Its totient is φ = 1521140020.

The previous prime is 1521140011. The next prime is 1521140053. The reversal of 1521140021 is 1200411251.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1441037521 + 80102500 = 37961^2 + 8950^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1521140021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1521140011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 760570010 + 760570011.

It is an arithmetic number, because the mean of its divisors is an integer number (760570011).

Almost surely, 2^1521140021 is an apocalyptic number.

It is an amenable number.

1521140021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1521140021 is an equidigital number, since it uses as much as digits as its factorization.

1521140021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 80, while the sum is 17.

The square root of 1521140021 is about 39001.7950997130. The cubic root of 1521140021 is about 1150.0667941040.

Adding to 1521140021 its reverse (1200411251), we get a palindrome (2721551272).

The spelling of 1521140021 in words is "one billion, five hundred twenty-one million, one hundred forty thousand, twenty-one".