20061551 has 4 divisors (see below), whose sum is σ = 20184792. Its totient is φ = 19938312.

The previous prime is 20061539. The next prime is 20061553. The reversal of 20061551 is 15516002.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20061551 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 (20061553) 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, 61376 + ... + 61701.

It is an arithmetic number, because the mean of its divisors is an integer number (5046198).

Almost surely, 2^20061551 is an apocalyptic number.

20061551 is a deficient number, since it is larger than the sum of its proper divisors (123241).

20061551 is a wasteful number, since it uses less digits than its factorization.

20061551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123240.

The product of its (nonzero) digits is 300, while the sum is 20.

The square root of 20061551 is about 4479.0122795098. The cubic root of 20061551 is about 271.7199350214.

Adding to 20061551 its reverse (15516002), we get a palindrome (35577553).

The spelling of 20061551 in words is "twenty million, sixty-one thousand, five hundred fifty-one".