921253621 has 2 divisors, whose sum is σ = 921253622. Its totient is φ = 921253620.

The previous prime is 921253591. The next prime is 921253633. The reversal of 921253621 is 126352129.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 595848100 + 325405521 = 24410^2 + 18039^2 .

It is an emirp because it is prime and its reverse (126352129) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-921253621 is a prime.

It is a super-2 number, since 2×921253621² = 1697416468411223282, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (921253651) 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, 460626810 + 460626811.

It is an arithmetic number, because the mean of its divisors is an integer number (460626811).

Almost surely, 2^921253621 is an apocalyptic number.

It is an amenable number.

921253621 is a deficient number, since it is larger than the sum of its proper divisors (1).

921253621 is an equidigital number, since it uses as much as digits as its factorization.

921253621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6480, while the sum is 31.

The square root of 921253621 is about 30352.1600714018. The cubic root of 921253621 is about 973.0303857827.

The spelling of 921253621 in words is "nine hundred twenty-one million, two hundred fifty-three thousand, six hundred twenty-one".