1521323381 has 2 divisors, whose sum is σ = 1521323382. Its totient is φ = 1521323380.

The previous prime is 1521323341. The next prime is 1521323389. The reversal of 1521323381 is 1833231251.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1507380625 + 13942756 = 38825^2 + 3734^2 .

It is a cyclic number.

It is not a de Polignac number, because 1521323381 - 2⁶ = 1521323317 is a prime.

It is a super-2 number, since 2×1521323381² = 4628849659154542322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1521323389) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 760661690 + 760661691.

It is an arithmetic number, because the mean of its divisors is an integer number (760661691).

Almost surely, 2^1521323381 is an apocalyptic number.

It is an amenable number.

1521323381 is a deficient number, since it is larger than the sum of its proper divisors (1).

1521323381 is an equidigital number, since it uses as much as digits as its factorization.

1521323381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4320, while the sum is 29.

The square root of 1521323381 is about 39004.1456899135. The cubic root of 1521323381 is about 1150.1130023803.

The spelling of 1521323381 in words is "one billion, five hundred twenty-one million, three hundred twenty-three thousand, three hundred eighty-one".