699020721 has 27 divisors (see below), whose sum is σ = 1175478681. Its totient is φ = 399123144.

The previous prime is 699020719. The next prime is 699020723. The reversal of 699020721 is 127020996.

The square root of 699020721 is 26439.

It is a perfect power (a square), and thus also a powerful number.

699020721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (699020719) and next prime (699020723).

It is not a de Polignac number, because 699020721 - 2¹ = 699020719 is a prime.

It is not an unprimeable number, because it can be changed into a prime (699020723) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 554590 + ... + 555848.

Almost surely, 2^699020721 is an apocalyptic number.

699020721 is the 26439-th square number.

699020721 is the 13220-th centered octagonal number.

It is an amenable number.

699020721 is a deficient number, since it is larger than the sum of its proper divisors (476457960).

699020721 is an equidigital number, since it uses as much as digits as its factorization.

699020721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2538 (or 1269 counting only the distinct ones).

The product of its (nonzero) digits is 13608, while the sum is 36.

The cubic root of 699020721 is about 887.4897581573.

Multiplying 699020721 by its sum of digits (36), we get a square (25164745956 = 158634²).

The spelling of 699020721 in words is "six hundred ninety-nine million, twenty thousand, seven hundred twenty-one".