921690031 has 2 divisors, whose sum is σ = 921690032. Its totient is φ = 921690030.

The previous prime is 921690013. The next prime is 921690061. The reversal of 921690031 is 130096129.

Together with previous prime (921690013) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is an emirp because it is prime and its reverse (130096129) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 921690031 - 2¹¹ = 921687983 is a prime.

It is a super-2 number, since 2×921690031² = 1699025026489561922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 921689975 and 921690002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (921690001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 460845015 + 460845016.

It is an arithmetic number, because the mean of its divisors is an integer number (460845016).

Almost surely, 2^921690031 is an apocalyptic number.

921690031 is a deficient number, since it is larger than the sum of its proper divisors (1).

921690031 is an equidigital number, since it uses as much as digits as its factorization.

921690031 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2916, while the sum is 31.

The square root of 921690031 is about 30359.3483296332. The cubic root of 921690031 is about 973.1840073067.

The spelling of 921690031 in words is "nine hundred twenty-one million, six hundred ninety thousand, thirty-one".