21971098 has 4 divisors (see below), whose sum is σ = 32956650. Its totient is φ = 10985548.

The previous prime is 21971083. The next prime is 21971107. The reversal of 21971098 is 89017912.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 21743569 + 227529 = 4663^2 + 477^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5492773 + ... + 5492776.

Almost surely, 2^21971098 is an apocalyptic number.

21971098 is a deficient number, since it is larger than the sum of its proper divisors (10985552).

21971098 is a wasteful number, since it uses less digits than its factorization.

21971098 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10985551.

The product of its (nonzero) digits is 9072, while the sum is 37.

The square root of 21971098 is about 4687.3337837197. Note that the first 3 decimals coincide. The cubic root of 21971098 is about 280.0811754436.

It can be divided in two parts, 2197 and 1098, that multiplied together give a triangular number (2412306 = T₂₁₉₆).

The spelling of 21971098 in words is "twenty-one million, nine hundred seventy-one thousand, ninety-eight".