1373621021 has 2 divisors, whose sum is σ = 1373621022. Its totient is φ = 1373621020.

The previous prime is 1373620993. The next prime is 1373621023. The reversal of 1373621021 is 1201263731.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1305376900 + 68244121 = 36130^2 + 8261^2 .

It is a cyclic number.

It is not a de Polignac number, because 1373621021 - 2⁶ = 1373620957 is a prime.

Together with 1373621023, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1373621023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 686810510 + 686810511.

It is an arithmetic number, because the mean of its divisors is an integer number (686810511).

Almost surely, 2^1373621021 is an apocalyptic number.

It is an amenable number.

1373621021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1373621021 is an equidigital number, since it uses as much as digits as its factorization.

1373621021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 1373621021 is about 37062.3936221070. The cubic root of 1373621021 is about 1111.6181849640.

Adding to 1373621021 its reverse (1201263731), we get a palindrome (2574884752).

The spelling of 1373621021 in words is "one billion, three hundred seventy-three million, six hundred twenty-one thousand, twenty-one".