98987921 has 4 divisors (see below), whose sum is σ = 99142512. Its totient is φ = 98833332.

The previous prime is 98987909. The next prime is 98987939. The reversal of 98987921 is 12978989.

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: 12978989 = 79 ⋅164291.

It is a cyclic number.

It is not a de Polignac number, because 98987921 - 2⁶ = 98987857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (98987951) 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, 76331 + ... + 77616.

It is an arithmetic number, because the mean of its divisors is an integer number (24785628).

Almost surely, 2^98987921 is an apocalyptic number.

It is an amenable number.

98987921 is a deficient number, since it is larger than the sum of its proper divisors (154591).

98987921 is a wasteful number, since it uses less digits than its factorization.

98987921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154590.

The product of its digits is 653184, while the sum is 53.

The square root of 98987921 is about 9949.2673599617. The cubic root of 98987921 is about 462.5876859311.

The spelling of 98987921 in words is "ninety-eight million, nine hundred eighty-seven thousand, nine hundred twenty-one".