2661406421 has 2 divisors, whose sum is σ = 2661406422. Its totient is φ = 2661406420.

The previous prime is 2661406417. The next prime is 2661406441. The reversal of 2661406421 is 1246041662.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2355646225 + 305760196 = 48535^2 + 17486^2 .

It is a cyclic number.

It is not a de Polignac number, because 2661406421 - 2² = 2661406417 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2661406441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1330703210 + 1330703211.

It is an arithmetic number, because the mean of its divisors is an integer number (1330703211).

Almost surely, 2^2661406421 is an apocalyptic number.

It is an amenable number.

2661406421 is a deficient number, since it is larger than the sum of its proper divisors (1).

2661406421 is an equidigital number, since it uses as much as digits as its factorization.

2661406421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13824, while the sum is 32.

The square root of 2661406421 is about 51588.8206978993. The cubic root of 2661406421 is about 1385.8101358388.

The spelling of 2661406421 in words is "two billion, six hundred sixty-one million, four hundred six thousand, four hundred twenty-one".