2121572491 has 2 divisors, whose sum is σ = 2121572492. Its totient is φ = 2121572490.

The previous prime is 2121572423. The next prime is 2121572503. The reversal of 2121572491 is 1942751212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2121572491 - 2⁷ = 2121572363 is a prime.

It is not a weakly prime, because it can be changed into another prime (2121572291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1060786245 + 1060786246.

It is an arithmetic number, because the mean of its divisors is an integer number (1060786246).

Almost surely, 2^2121572491 is an apocalyptic number.

2121572491 is a deficient number, since it is larger than the sum of its proper divisors (1).

2121572491 is an equidigital number, since it uses as much as digits as its factorization.

2121572491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10080, while the sum is 34.

The square root of 2121572491 is about 46060.5307285967. The cubic root of 2121572491 is about 1284.9492005535.

The spelling of 2121572491 in words is "two billion, one hundred twenty-one million, five hundred seventy-two thousand, four hundred ninety-one".