1231624921 has 2 divisors, whose sum is σ = 1231624922. Its totient is φ = 1231624920.

The previous prime is 1231624913. The next prime is 1231624991. The reversal of 1231624921 is 1294261321.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1172103696 + 59521225 = 34236^2 + 7715^2 .

It is an emirp because it is prime and its reverse (1294261321) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1231624921 - 2³ = 1231624913 is a prime.

It is not a weakly prime, because it can be changed into another prime (1231624991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615812460 + 615812461.

It is an arithmetic number, because the mean of its divisors is an integer number (615812461).

Almost surely, 2^1231624921 is an apocalyptic number.

It is an amenable number.

1231624921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231624921 is an equidigital number, since it uses as much as digits as its factorization.

1231624921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5184, while the sum is 31.

The square root of 1231624921 is about 35094.5141154568. The cubic root of 1231624921 is about 1071.9128798032.

The spelling of 1231624921 in words is "one billion, two hundred thirty-one million, six hundred twenty-four thousand, nine hundred twenty-one".