740689021 has 2 divisors, whose sum is σ = 740689022. Its totient is φ = 740689020.

The previous prime is 740689013. The next prime is 740689039. The reversal of 740689021 is 120986047.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 729540100 + 11148921 = 27010^2 + 3339^2 .

It is a cyclic number.

It is not a de Polignac number, because 740689021 - 2³ = 740689013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (740689091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 370344510 + 370344511.

It is an arithmetic number, because the mean of its divisors is an integer number (370344511).

Almost surely, 2^740689021 is an apocalyptic number.

It is an amenable number.

740689021 is a deficient number, since it is larger than the sum of its proper divisors (1).

740689021 is an equidigital number, since it uses as much as digits as its factorization.

740689021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24192, while the sum is 37.

The square root of 740689021 is about 27215.6025286967. The cubic root of 740689021 is about 904.7848133619.

The spelling of 740689021 in words is "seven hundred forty million, six hundred eighty-nine thousand, twenty-one".