2121551 has 4 divisors (see below), whose sum is σ = 2151504. Its totient is φ = 2091600.

The previous prime is 2121529. The next prime is 2121569. The reversal of 2121551 is 1551212.

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-2121551 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 (2121751) 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, 14870 + ... + 15011.

It is an arithmetic number, because the mean of its divisors is an integer number (537876).

2^2121551 is an apocalyptic number.

2121551 is a deficient number, since it is larger than the sum of its proper divisors (29953).

2121551 is an equidigital number, since it uses as much as digits as its factorization.

2121551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29952.

The product of its digits is 100, while the sum is 17.

The square root of 2121551 is about 1456.5544960625. The cubic root of 2121551 is about 128.4944861801.

Adding to 2121551 its reverse (1551212), we get a palindrome (3672763).

The spelling of 2121551 in words is "two million, one hundred twenty-one thousand, five hundred fifty-one".