646969690 has 32 divisors (see below), whose sum is σ = 1209406464. Its totient is φ = 248920320.

The previous prime is 646969669. The next prime is 646969693. The reversal of 646969690 is 96969646.

It is a super-2 number, since 2×646969690² = 837139559557392200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (646969693) 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, 45522 + ... + 58018.

It is an arithmetic number, because the mean of its divisors is an integer number (37793952).

Almost surely, 2^646969690 is an apocalyptic number.

646969690 is a deficient number, since it is larger than the sum of its proper divisors (562436774).

646969690 is a wasteful number, since it uses less digits than its factorization.

646969690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12702.

The product of its (nonzero) digits is 3779136, while the sum is 55.

The square root of 646969690 is about 25435.5988724465. The cubic root of 646969690 is about 864.8908679855.

The spelling of 646969690 in words is "six hundred forty-six million, nine hundred sixty-nine thousand, six hundred ninety".