187422821 has 4 divisors (see below), whose sum is σ = 197287200. Its totient is φ = 177558444.

The previous prime is 187422811. The next prime is 187422827. The reversal of 187422821 is 128224781.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 128224781 = 149 ⋅860569.

It is a cyclic number.

It is not a de Polignac number, because 187422821 - 2⁶ = 187422757 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 (187422827) 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, 4932161 + ... + 4932198.

It is an arithmetic number, because the mean of its divisors is an integer number (49321800).

Almost surely, 2^187422821 is an apocalyptic number.

It is an amenable number.

187422821 is a deficient number, since it is larger than the sum of its proper divisors (9864379).

187422821 is an equidigital number, since it uses as much as digits as its factorization.

187422821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9864378.

The product of its digits is 14336, while the sum is 35.

The square root of 187422821 is about 13690.2454689461. The cubic root of 187422821 is about 572.2785790320.

The spelling of 187422821 in words is "one hundred eighty-seven million, four hundred twenty-two thousand, eight hundred twenty-one".