20993554 has 4 divisors (see below), whose sum is σ = 31490334. Its totient is φ = 10496776.

The previous prime is 20993543. The next prime is 20993591. The reversal of 20993554 is 45539902.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 45539902 = 2 ⋅22769951.

It can be written as a sum of positive squares in only one way, i.e., 20912329 + 81225 = 4573^2 + 285^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5248387 + ... + 5248390.

Almost surely, 2^20993554 is an apocalyptic number.

20993554 is a deficient number, since it is larger than the sum of its proper divisors (10496780).

20993554 is a wasteful number, since it uses less digits than its factorization.

20993554 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10496779.

The product of its (nonzero) digits is 48600, while the sum is 37.

The square root of 20993554 is about 4581.8723247162. The cubic root of 20993554 is about 275.8641861378.

The spelling of 20993554 in words is "twenty million, nine hundred ninety-three thousand, five hundred fifty-four".