20979554 has 4 divisors (see below), whose sum is σ = 31469334. Its totient is φ = 10489776.

The previous prime is 20979551. The next prime is 20979559. The reversal of 20979554 is 45597902.

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., 20948929 + 30625 = 4577^2 + 175^2 .

It is not an unprimeable number, because it can be changed into a prime (20979551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5244887 + ... + 5244890.

Almost surely, 2^20979554 is an apocalyptic number.

20979554 is a deficient number, since it is larger than the sum of its proper divisors (10489780).

20979554 is a wasteful number, since it uses less digits than its factorization.

20979554 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10489779.

The product of its (nonzero) digits is 113400, while the sum is 41.

The square root of 20979554 is about 4580.3443102020. The cubic root of 20979554 is about 275.8028505261.

The spelling of 20979554 in words is "twenty million, nine hundred seventy-nine thousand, five hundred fifty-four".