99931421 has 4 divisors (see below), whose sum is σ = 99960000. Its totient is φ = 99902844.

The previous prime is 99931417. The next prime is 99931439. The reversal of 99931421 is 12413999.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12413999 = 13 ⋅954923.

It is a cyclic number.

It is not a de Polignac number, because 99931421 - 2² = 99931417 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99931411) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8171 + ... + 16328.

It is an arithmetic number, because the mean of its divisors is an integer number (24990000).

Almost surely, 2^99931421 is an apocalyptic number.

It is an amenable number.

99931421 is a deficient number, since it is larger than the sum of its proper divisors (28579).

99931421 is a wasteful number, since it uses less digits than its factorization.

99931421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28578.

The product of its digits is 17496, while the sum is 38.

The square root of 99931421 is about 9996.5704619134. The cubic root of 99931421 is about 464.0527539232.

The spelling of 99931421 in words is "ninety-nine million, nine hundred thirty-one thousand, four hundred twenty-one".