999987421 has 2 divisors, whose sum is σ = 999987422. Its totient is φ = 999987420.

The previous prime is 999987409. The next prime is 999987427. The reversal of 999987421 is 124789999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 836019396 + 163968025 = 28914^2 + 12805^2 .

It is a cyclic number.

It is not a de Polignac number, because 999987421 - 2⁵ = 999987389 is a prime.

It is a nialpdrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999987427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499993710 + 499993711.

It is an arithmetic number, because the mean of its divisors is an integer number (499993711).

Almost surely, 2^999987421 is an apocalyptic number.

It is an amenable number.

999987421 is a deficient number, since it is larger than the sum of its proper divisors (1).

999987421 is an equidigital number, since it uses as much as digits as its factorization.

999987421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2939328, while the sum is 58.

The square root of 999987421 is about 31622.5777096049. The cubic root of 999987421 is about 999.9958069824.

The spelling of 999987421 in words is "nine hundred ninety-nine million, nine hundred eighty-seven thousand, four hundred twenty-one".