921865393 has 2 divisors, whose sum is σ = 921865394. Its totient is φ = 921865392.

The previous prime is 921865381. The next prime is 921865423. The reversal of 921865393 is 393568129.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 508637809 + 413227584 = 22553^2 + 20328^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-921865393 is a prime.

It is a super-2 number, since 2×921865393² = 1699671605622088898, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (921865493) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 460932696 + 460932697.

It is an arithmetic number, because the mean of its divisors is an integer number (460932697).

Almost surely, 2^921865393 is an apocalyptic number.

It is an amenable number.

921865393 is a deficient number, since it is larger than the sum of its proper divisors (1).

921865393 is an equidigital number, since it uses as much as digits as its factorization.

921865393 is an evil number, because the sum of its binary digits is even.

The product of its digits is 349920, while the sum is 46.

The square root of 921865393 is about 30362.2362977433. The cubic root of 921865393 is about 973.2457231641.

It can be divided in two parts, 92186 and 5393, that added together give a palindrome (97579).

The spelling of 921865393 in words is "nine hundred twenty-one million, eight hundred sixty-five thousand, three hundred ninety-three".