1021605139 has 2 divisors, whose sum is σ = 1021605140. Its totient is φ = 1021605138.

The previous prime is 1021605121. The next prime is 1021605149. The reversal of 1021605139 is 9315061201.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1021605139 - 2¹¹ = 1021603091 is a prime.

It is not a weakly prime, because it can be changed into another prime (1021605149) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510802569 + 510802570.

It is an arithmetic number, because the mean of its divisors is an integer number (510802570).

Almost surely, 2^1021605139 is an apocalyptic number.

1021605139 is a deficient number, since it is larger than the sum of its proper divisors (1).

1021605139 is an equidigital number, since it uses as much as digits as its factorization.

1021605139 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1620, while the sum is 28.

The square root of 1021605139 is about 31962.5583925943. The cubic root of 1021605139 is about 1007.1504620272.

The spelling of 1021605139 in words is "one billion, twenty-one million, six hundred five thousand, one hundred thirty-nine".