491261251 has 8 divisors (see below), whose sum is σ = 529314464. Its totient is φ = 453245760.

The previous prime is 491261237. The next prime is 491261269. The reversal of 491261251 is 152162194.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 491261251 - 2²¹ = 489164099 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (491261201) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21370 + ... + 37936.

It is an arithmetic number, because the mean of its divisors is an integer number (66164308).

Almost surely, 2^491261251 is an apocalyptic number.

491261251 is a deficient number, since it is larger than the sum of its proper divisors (38053213).

491261251 is a wasteful number, since it uses less digits than its factorization.

491261251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18861.

The product of its digits is 4320, while the sum is 31.

The square root of 491261251 is about 22164.4140685018. The cubic root of 491261251 is about 789.0493564253.

The spelling of 491261251 in words is "four hundred ninety-one million, two hundred sixty-one thousand, two hundred fifty-one".