61821291 has 32 divisors (see below), whose sum is σ = 97561600. Its totient is φ = 34800192.

The previous prime is 61821271. The next prime is 61821323. The reversal of 61821291 is 19212816.

It is a happy number.

It is not a de Polignac number, because 61821291 - 2⁵ = 61821259 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61821251) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 74706 + ... + 75528.

It is an arithmetic number, because the mean of its divisors is an integer number (3048800).

Almost surely, 2^61821291 is an apocalyptic number.

61821291 is a deficient number, since it is larger than the sum of its proper divisors (35740309).

61821291 is an equidigital number, since it uses as much as digits as its factorization.

61821291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 920 (or 906 counting only the distinct ones).

The product of its digits is 1728, while the sum is 30.

The square root of 61821291 is about 7862.6516519556. The cubic root of 61821291 is about 395.4085203621.

The spelling of 61821291 in words is "sixty-one million, eight hundred twenty-one thousand, two hundred ninety-one".