690657621 has 16 divisors (see below), whose sum is σ = 941580288. Its totient is φ = 450110000.

The previous prime is 690657607. The next prime is 690657631. The reversal of 690657621 is 126756096.

It is a cyclic number.

It is not a de Polignac number, because 690657621 - 2¹⁰ = 690656597 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (690657631) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 142996 + ... + 147746.

It is an arithmetic number, because the mean of its divisors is an integer number (58848768).

Almost surely, 2^690657621 is an apocalyptic number.

It is an amenable number.

690657621 is a deficient number, since it is larger than the sum of its proper divisors (250922667).

690657621 is a wasteful number, since it uses less digits than its factorization.

690657621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5832.

The product of its (nonzero) digits is 136080, while the sum is 42.

The square root of 690657621 is about 26280.3656938027. The cubic root of 690657621 is about 883.9362327999.

The spelling of 690657621 in words is "six hundred ninety million, six hundred fifty-seven thousand, six hundred twenty-one".