1697421690 has 64 divisors (see below), whose sum is σ = 4554345600. Its totient is φ = 449857152.

The previous prime is 1697421673. The next prime is 1697421697. The reversal of 1697421690 is 961247961.

1697421690 is a `hidden beast` number, since 169 + 7 + 421 + 69 + 0 = 666.

It is a super-2 number, since 2×1697421690² = 5762480787364912200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (1697421697) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 24726 + ... + 63294.

It is an arithmetic number, because the mean of its divisors is an integer number (71161650).

Almost surely, 2^1697421690 is an apocalyptic number.

1697421690 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1697421690, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2277172800).

1697421690 is an abundant number, since it is smaller than the sum of its proper divisors (2856923910).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1697421690 is a wasteful number, since it uses less digits than its factorization.

1697421690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38748 (or 38742 counting only the distinct ones).

The product of its (nonzero) digits is 163296, while the sum is 45.

The square root of 1697421690 is about 41199.7777906629. Note that the first 4 decimals coincide. The cubic root of 1697421690 is about 1192.8795200397.

The spelling of 1697421690 in words is "one billion, six hundred ninety-seven million, four hundred twenty-one thousand, six hundred ninety".