1420155721 has 2 divisors, whose sum is σ = 1420155722. Its totient is φ = 1420155720.

The previous prime is 1420155697. The next prime is 1420155743. The reversal of 1420155721 is 1275510241.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1419782400 + 373321 = 37680^2 + 611^2 .

It is a cyclic number.

It is not a de Polignac number, because 1420155721 - 2²³ = 1411767113 is a prime.

It is a super-3 number, since 3×1420155721³ (a number of 28 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1420155721.

It is not a weakly prime, because it can be changed into another prime (1420155761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 710077860 + 710077861.

It is an arithmetic number, because the mean of its divisors is an integer number (710077861).

Almost surely, 2^1420155721 is an apocalyptic number.

It is an amenable number.

1420155721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1420155721 is an equidigital number, since it uses as much as digits as its factorization.

1420155721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2800, while the sum is 28.

The square root of 1420155721 is about 37684.9535093252. The cubic root of 1420155721 is about 1124.0319497278.

Adding to 1420155721 its reverse (1275510241), we get a palindrome (2695665962).

The spelling of 1420155721 in words is "one billion, four hundred twenty million, one hundred fifty-five thousand, seven hundred twenty-one".