261942979 has 2 divisors, whose sum is σ = 261942980. Its totient is φ = 261942978.

The previous prime is 261942913. The next prime is 261942983. The reversal of 261942979 is 979249162.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261942979 is a prime.

It is a super-2 number, since 2×261942979² = 137228248494788882, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (261942679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130971489 + 130971490.

It is an arithmetic number, because the mean of its divisors is an integer number (130971490).

Almost surely, 2^261942979 is an apocalyptic number.

261942979 is a deficient number, since it is larger than the sum of its proper divisors (1).

261942979 is an equidigital number, since it uses as much as digits as its factorization.

261942979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 489888, while the sum is 49.

The square root of 261942979 is about 16184.6525758201. The cubic root of 261942979 is about 639.8363668578.

The spelling of 261942979 in words is "two hundred sixty-one million, nine hundred forty-two thousand, nine hundred seventy-nine".