19992557 has 4 divisors (see below), whose sum is σ = 21530460. Its totient is φ = 18454656.

The previous prime is 19992529. The next prime is 19992569. The reversal of 19992557 is 75529991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 75529991 = 113 ⋅668407.

It can be written as a sum of positive squares in 2 ways, for example, as 13586596 + 6405961 = 3686^2 + 2531^2 .

It is a cyclic number.

It is not a de Polignac number, because 19992557 - 2¹² = 19988461 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 (19992517) 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, 768932 + ... + 768957.

It is an arithmetic number, because the mean of its divisors is an integer number (5382615).

Almost surely, 2^19992557 is an apocalyptic number.

It is an amenable number.

19992557 is a deficient number, since it is larger than the sum of its proper divisors (1537903).

19992557 is a wasteful number, since it uses less digits than its factorization.

19992557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1537902.

The product of its digits is 255150, while the sum is 47.

The square root of 19992557 is about 4471.3037248659. The cubic root of 19992557 is about 271.4080851310.

The spelling of 19992557 in words is "nineteen million, nine hundred ninety-two thousand, five hundred fifty-seven".